This sounds like it could be done fairly simply it just depends on how they are getting to the records I guess.
Have some kind of identifier on the record that says the type it is. Have a formula that then determines the right dfid based on the type. You may need to create your own edit and view buttons, this can be done in rich text and used to replace the the native buttons by hiding the native ones in the report itself. This would allow the edit and view buttons to take into account the dfid formula I mentioned above and take users to the correct form based on the doc type.
I can break that down further into actual code that may be needed if you want, let me know. I figured just giving the idea for now might spark something.
