Recently we are deploying the TM1 model to few other countries. Now I'm at stage of planning the user groups . I noticed there's quite a lot of user groups that I need to create, and I have been cracking my heads for better ways in doing it.. but still no avails. Hence, am thinking of posting my situtation here, to see if anyone can suggest me alternatives

Below is my situation ..
I'm implementing to Country A, B, C, D,E. Product Managers will be using the system. Each product manager takes care of their own group of product, e.g. Product 1, 2, 3, 4, 5.
We have a cube, called sales cube, where stores the sales information. This sales cube consists of all sales data for all these countries, and we want to allow only the right product manager of the right country to have access to his own data.
I plan to have 25 groups. A1, A2, A3, A4, A5, B1, B2, etc.
At the Dimension Security for Country, I allow for all A* to access to only A, B* to access only B, etc.
I create a seperate cube to maintain the security. For A1, access only product 1(and the child under it), A2, access only product 2(and the child under it), , B1 access only product 1(and the child under it), , etc
At the Cube Security, I grant all users to READ Sales cube.
Is there any cleverer way of doing this? I feel my method is quite high in maintenance...
Pls share your view