Our project has about 4 separate git roots.
(At least that's what most developers work with. There are additional related projects like different clients, so that some developers work with 6 or more git roots.)
Currently IDEA support for this is too limited imho:
The point of view is still on individual git roots.
Only if all git roots are currently on the same branch (as determined by branch name), then you get the chance of operating on all git roots at the same time.
For me this does not really work. Often times I have a branch on only two or three git roots.
What would help me is a perspective on git that is centered on branches, i.e. see all branches, the select one branch and see all affected git roots.
Creating a new branch would allow me to select which git roots should get the branch.
How do others work with multiple git roots?
Would that help you, too?