My team would like to have the ability to have one user, A, be a lead developer on project X, for example. However, we want user A to not be a lead developer and be a regular developer on project Y. We want the user to have different permissions (closing issues, etc.) on the two projects. Would I simply use a project role for this? I'm trying to figure out what the difference is between a user group and a project role. I understand the role is project specific but the user group is global, but I don't see how a user group would be helpful for us for these kinds of situations.