It would be nice if you could have let's say 2 accounts in the same access level, and assign different/specific categories they have access to....

Am I making any sense ? Is this possible ?

I see what you mean but it would be just as easy to create an additional access level with all the same settings as the first, then just change which categories each can access.

Yes, but let's say there is a club that have many leaders, and each leader is a coach for let's say 4 different teams. You can only assign one access level to an account...

Sorry for my poor explanation..but I think you know what I mean ?

The way I would go about it would be to create additional access levels for each leader then assign the accounts to those access levels. It just means they'd all be able to access the same settings within the system the only difference is they can post in different categories.