How to auto synchronize users and their roles in Musites

For example, I assign user roles as following:

role A in subsite A
role B in subsite B
role C in subsite C

and if users in subsite A finished some task, his role will automatically upgrade to Role B, and got permission to access B, but no permission to access Subsite C yet.

I know permission in every subsite is up to role capability, so my only question here is how should I make users role auto synchronized in whole Musites? can I Role Scoper to do that, or should I use any other plugin?

Thanks so much, have a nice day.

Alex