Projects - limit task and sub-project team member selection to parent project team membership

Under normal circumstances task and sub-project team membership should be limited to the members of the immediate parent project's team.

So if we have a project/tasks hierarchy as follows, with corresponding team members in braces, the bold and underlined team memberships would not be prevented, in Task 3, bill could not be a member of the Task team, because he was not a member of the parent project (Sub-Project 1) team and in Sub-Project 2, peter could not be a member of the sub-project team, because he was not a member of the parent project (Top Level Project) team:

• Top Level Project (fred, joe, sally, jane, bill)
  • Sub-Project 1 (fred, sally, jane)
    • Task 1 (sally)
    • Task 2 (fred, jane)
    • Task 3 (fred, bill)
  • Sub-Project 2 (fred, joe, peter)