Permissions and User roles

[Sylvia]

We are using TestLink as an enterprise wide Test Management Tool in our organisation. We are facing an issue where we need the Test/Project Manager to assign only roles to their team members but not have the ability to add or remove the Team members from their projects. Is there a way to do this? As of now what we see is, only the Admin has the ability to also assign new roles, we do not want the Project/Test Manager to have admin priveldges as they are able to see that data of all other projects and also the ability to change the team member of other projects. This is looking like a show stopper for us as of now, your inputs to address this issue will be greatly appreciated.