lead distribution form adaptation - repost

We are in need of a web developer to do a bit of work with a lead distribution system we use. Basically, we are renting a system that stores and redistributes sales leads that we generate (we have only just started with it and are in testing at the moment) we have found that it does most things apart from returning the page after form submission to a variable thankyou page. (ie if the lead goes to supplier A, the thankyou page reflects Supplier A's profile and if the lead goes to supplier B, the thankyou page reflects Supplier B's profile etc). at the moment there is only the facility to have a generic thankyou page regardless of which supplier the lead goes to. Our contact at FLG (company who created the system) says to amend this so that the form returns to the correct thankyou page is a simple task for a developer however it is way above my understanding. I can supply you with the logins and the User guides that FLG has sent us.