Hi there, @kevin35… I might have to think this one through a bit more, but if you want to use privacy rules (which have a well-documented limitation), I believe you would need to have multiple list fields on either the User data type or the Project data type, and each list field would be associated with a specific role. So, you would either have multiple list fields on the User data type that store lists of projects for each role or you would have multiple list fields on the Project data type that store lists of users for each role. With those list fields in place, you should be able to build the necessary privacy rules by checking to see if a project is in a user’s specific role field or if a user is in a project’s specific role field.
Another way to go would be to use an option set to define the roles and then have a custom data type that stores the association between a user, a project, and the user’s role on the project. With this structure, I don’t believe you would be able to use privacy rules, though, because of the aforementioned limitation.
Anyway, just some food for thought there, I guess, and I hope it helps.
Best…
Mike