permissions on a custom DataView

Hi - I have built a custom dataform object that takes a parameter to determine what to show. However, I wanted to put it on several different pages - and have the permissions on each page be visible to different roles. I am not getting a way from support to do this. I can set different tasks with different permissions, but if someone shares the url directly, it seems like anyone can see any page, since I need to make the dataform available to all groups. When I asked support, their only suggestion was to use expressions to control visibility of the tab, but it seems those expressions cannot use roles in the different definitions. Does anyone have a different idea? Thanks!

Here is what I had posed to support:

I have 3 pages that all use the same dataform. I want the permissions for each page to be different, i.e. group A can get to page A, group B to page B and group C to page C. I can see that I need to set the permissions for the dataform to be accessible to groups A, B, C and that I can set up 3 tasks and set the permissions on each task. But, if someone shares the url to page A to someone in group B, I don't see how to prevent group B from not being able to see the page? The dataform differs on each page by its parameter settings.