If anybody interesting I have found a workaround...

Create a special location eg : PROD 

Create a couple a child to this location PROD1 , PROD2 , PROD3 , etc....

Create a as many production routing as location created to do the raw material picking in a location (eg : ROUTING1 -> raw material picking in location PROD1 , ROUTING2 -> raw material picking in location PROD2 , etc...)

So the setup is ready to use.

Use cas : 

Creation of a sales order for two products configured with routes (manufacture, make to order).

These two products have both a bill of material (1st is configured with ROUTING1 and 2nd with ROUTING2)

The mrp generate two manufacturing orders to produce both products. 

Because of the different raw material picking locations in each routing the system created two different internal move to supply each manufactoring orders and doesn't not group them in a single internal move because the procurement rules doesn't match because of the routings we created.