diff --git a/README.md b/README.md
index 7744743..d339823 100644
--- a/README.md
+++ b/README.md
@@ -10,7 +10,7 @@ $ curl -#fL "$(curl -s https://api.github.com/repos/NINEJKH/myformer/releases/la
 
 ## Example
 
-create structure dump
+### create structure dump
 
 ```bash
 $ mysqldump \
@@ -22,7 +22,7 @@ $ mysqldump \
   > database_structure.sql
 ```
 
-create data dump
+### create data dump
 
 ```bash
 $ mysqldump \
@@ -36,24 +36,24 @@ $ mysqldump \
   > database_data.sql
 ```
 
-create config
+### create config
 
 ```bash
 $ cat <<'EOF' > .myform.json
 {
     "table_name": [{
             "columnA": {
-                "Tel": []
+                "Tel": null
             } 
         },
         {
             "columnB": {
-                "Email": []
+                "Email": "qa+%s@company.com"
             }
         },
         {
             "columnC": {
-                "Replace": ["foo", "bar"]
+                "Set": "static content"
             }
         }
     ]
@@ -61,8 +61,34 @@ $ cat <<'EOF' > .myform.json
 EOF
 ```
 
-anonymise data
+### anonymise data
 
 ```bash
-$ myformer
+$ myformer transform *_data.sql
 ```
+
+This will create a file with the same name + postfixed with "+transformed".
+
+## Rules
+
+### Email
+
+Anonymise Email addresses.
+
+Accepts a string parameter, `%s` will be replaced with the first 16 chars
+of the md5 hash of the original value. 
+
+### Ref
+
+Set column value from another column value.
+
+Accepts a string parameter, which will be used as column name of the
+source value.
+
+### Set
+
+Statically set the value of the string parameter
+
+### Tel
+
+Random telphone-like number (999 + 10-digits)
diff --git a/app/Transformer/Condition.php b/app/Transformer/Condition.php
new file mode 100644
index 0000000..92add03
--- /dev/null
+++ b/app/Transformer/Condition.php
@@ -0,0 +1,13 @@
+<?php
+
+namespace App\Transformer;
+
+abstract class Condition implements ConditionInterface
+{
+    protected $param;
+
+    public function __construct($param)
+    {
+        $this->param = $param;
+    }
+}
diff --git a/app/Transformer/ConditionInterface.php b/app/Transformer/ConditionInterface.php
new file mode 100644
index 0000000..f66fa55
--- /dev/null
+++ b/app/Transformer/ConditionInterface.php
@@ -0,0 +1,8 @@
+<?php
+
+namespace App\Transformer;
+
+interface ConditionInterface
+{
+    public function evaluate($against);
+}
diff --git a/app/Transformer/Conditions/Contains.php b/app/Transformer/Conditions/Contains.php
new file mode 100644
index 0000000..e5c3f01
--- /dev/null
+++ b/app/Transformer/Conditions/Contains.php
@@ -0,0 +1,13 @@
+<?php
+
+namespace App\Transformer\Conditions;
+
+use App\Transformer\Condition;
+
+class Contains extends Condition
+{
+    public function evaluate($against)
+    {
+        return (bool) stripos($against, $this->param);
+    }
+}
diff --git a/app/Transformer/Rule.php b/app/Transformer/Rule.php
new file mode 100644
index 0000000..df04deb
--- /dev/null
+++ b/app/Transformer/Rule.php
@@ -0,0 +1,43 @@
+<?php
+
+namespace App\Transformer;
+
+class Rule
+{
+    public $column;
+
+    public $name;
+
+    public $param;
+
+    public $condition;
+
+    public function __construct($column, array $rule)
+    {
+        $this->column = $column;
+
+        $this->extractNameAndParam($rule);
+    }
+
+    protected function extractNameAndParam(array $rule)
+    {
+        if (count($rule) === 1) {
+            $this->name = key($rule);
+            $this->param = current($rule);
+        } else {
+            if (isset($rule['Condition'])) {
+                $condition_class = 'App\\Transformer\\Conditions\\' . key($rule['Condition']);
+                $this->condition = new $condition_class(current($rule['Condition']));
+                //$this->condition = [
+                //    'name' => key($rule['Condition']),
+                //    'param' => current($rule['Condition']),
+                //];
+
+                unset($rule['Condition']);
+            }
+
+            $this->name = key($rule);
+            $this->param = current($rule);
+        }
+    }
+}
diff --git a/app/Transformer/RuleSet.php b/app/Transformer/RuleSet.php
new file mode 100644
index 0000000..ccf5f26
--- /dev/null
+++ b/app/Transformer/RuleSet.php
@@ -0,0 +1,59 @@
+<?php
+
+namespace App\Transformer;
+
+use Iterator;
+
+class RuleSet implements Iterator
+{
+    protected $rules = [];
+
+    protected $column = [];
+
+    protected $pos;
+
+    public function __construct(array $rules)
+    {
+        $this->rules = $rules;
+        $this->columns = array_keys($rules);
+        $this->pos = 0;
+    }
+
+    public function next()
+    {
+        ++$this->pos;
+    }
+
+    public function valid()
+    {
+        return isset($this->columns[$this->pos]);
+    }
+
+    public function current()
+    {
+        $column = $this->columns[$this->pos];
+        $rule = $this->rules[$column];
+
+        if (isset($rule[0])) {
+            $rules = [];
+
+            foreach($rule as $each) {
+                $rules[] = new Rule($column, $each);
+            }
+
+            return $rules;
+        } else {
+            return new Rule($column, $rule);
+        }
+    }
+
+    public function rewind()
+    {
+        $this->pos = 0;
+    }
+
+    public function key()
+    {
+        return $this->pos;
+    }
+}
diff --git a/app/Transformer/Transform.php b/app/Transformer/Transform.php
index dcd9dba..9c6018b 100644
--- a/app/Transformer/Transform.php
+++ b/app/Transformer/Transform.php
@@ -60,23 +60,51 @@ protected function build($table, array $columns, array $values)
     protected function map(array $columns, array $values, array $mappings)
     {
         $columns_n = array_flip($columns);
+        $ruleset = new RuleSet($mappings);
 
-        foreach ($mappings as $column => $rule) {
-            $rule_name = key($rule);
+        foreach ($ruleset as $rule) {
+            $this->transformValues($rule, $columns_n, $values);
+        }
 
-            if (!isset($this->transformers[$rule_name])) {
-                $class_name = 'App\\Transformer\\Transformers\\' . $rule_name;
-                $this->transformers[$rule_name] = new $class_name;
-                $this->transformers[$rule_name]->setParam(current($rule));
-            }
+        return $values;
+    }
 
-            foreach ($values as $n => $value_group) {
-                $column_n = $columns_n[$column];
-                $values[$n][$column_n] = $this->transformers[$rule_name]->transform($columns_n, $value_group, $column_n);
+    protected function transformValues($rule, array $columns_n, array &$values)
+    {
+        foreach ($values as $n => $value_group) {
+            $transformer = null;
+
+            if (is_array($rule)) {
+                foreach ($rule as $each) {
+                    if ($each->condition === null || $each->condition->evaluate($values[$n][$columns_n[$each->column]])) {
+                        $column_n = $columns_n[$each->column];
+                        $transformer = $this->getTransformer($each);
+                        break;
+                    }
+                }
+
+                if (!$transformer) {
+                    continue;
+                }
+
+            } else {
+                $transformer = $this->getTransformer($rule);
+                $column_n = $columns_n[$rule->column];
             }
 
+
+            $values[$n][$column_n] = $transformer->transform($columns_n, $value_group, $column_n);
         }
+    }
 
-        return $values;
+    protected function getTransformer(Rule $rule)
+    {
+        if (!isset($this->transformers[$rule->name])) {
+            $class_name = 'App\\Transformer\\Transformers\\' . $rule->name;
+            $this->transformers[$rule->name] = new $class_name;
+            $this->transformers[$rule->name]->setParam($rule->param);
+        }
+
+        return $this->transformers[$rule->name];
     }
 }