Hi,
If I understand your problem correctly then I would suggest you to try this (never tried it so I do not know if it will work):
1/
Create a forth form that contains all of the fields of the 3 other forms.
2/
Make sure your view selection formula includes documents created with your 3 forms.
3/
Add a form formula to the view that opens each document with the new form instead of it's own.
If this does not work you will need to add a "form" field to the 3 existing forms that specify then forth form name. However this will cause all documents to be opened with the new form also if you do not overule it.
You can also work with a form "alias" that will allow you to flexible use one or the other form to open the document.
You might also consider creating a total different structure of your views or to re-structure your entire application. Put all data in 1 form, and work with hide-when formulas and "Next" and Previous" buttons to give the user the feeling he has 3 different screens for example. Many more possibilities.
Remember: if you want data of 3 forms in 1 line of a view, then you need to get all data in 1 form first. That does not mean copying the actual data, but displaying the documents in a common form.
Personally I have never seen a request such as yours so I think you might need to reconsider your database design.
Hope this helps!
Kind regards,
Dominik Malfait
dominik@amazingit.com