Suresh's comments are valid and I would certainly suggest taking a look at those. However, I believe that what you want is a little different than what Suresh is suggesting.
In JavaScript I do something similar to what I think you want to do. You can use the following code to change to another form. In my form_load event for each form I have logic that deteremines which form the user needs to be on, then redirects
them if need be. For what I am doing, I have a lot of logic setup to control which form based on a user's roles, the current state of the record, etc.
You'll have to figure out the index of each of the forms (probably 0 or 1) by trail and error. I don't know of a valid way to resolve the index. I believe it is just a 0-based array based on how you have the ordered. So if you change the
order, be aware that this code might need to be adjusted. But it should be easy to test and adjust it as needed.
Xrm.Page.ui.formSelector.items.get(formIndex).navigate();
Jon Gregory Rothlander