Part 2 of this blog can be read here
Scenario 5: PM to only add Generic resources to their Project Team whereas Resources Managers should be adding specific resources.
Bob the PM Should not directly be assigning actual people to its Project. Instead, he should be assigning Generic Resources. A resource manager can later add specific resources. Once specific resources are added, PM should be able to assign tasks to those specific resources as well.
Solution:
1) PMs by default have permission to assign any resource. To remove this permission, Go to Server Settings -> Manage Groups,