Membership API in asp.net

As I get deeper into my current project, I realize it is a lot more complex than I thought. In my last question I mentioned that I needed to create a bunch of unique user roles, such as:

stocking
checking
customer-service
complaints

I've been using the Capabilities Manager plugin to create the roles I need. But now I realize the number of different kinds of roles needed on this site is going to be crazy complex. I've already created over 25 roles and every time I talk to the project manager we realize we need another 5 or 10. The problem is the kinds of combinations that keep coming up. For instance:

stocking:
ability to add
ability to edit
ability to delete


checking:
ability to add
ability to edit
ability to delete


customer-service:
ability to add
ability to edit
ability to delete


complaints:
ability to add
ability to edit
ability to delete


stocking and checking:
ability to add
ability to edit
ability to delete


stocking and customer-service:
ability to add
ability to edit
ability to delete


stocking and complaints:
ability to add
ability to edit
ability to delete


stocking and checking and customer-service:
ability to add
ability to edit
ability to delete

stocking and checking and complaints:
ability to add
ability to edit
ability to delete


You get the idea? But instead of 4 base items, we've got 14. So the number of combinations is going to be in the hundreds.

So I am wondering, can I assign more than one user role to a user? Or can I create groups? I know a lot of other CMS software allows for groups and multiple roles. Joomla, for instance. Can I do anything like that with WordPress? We've already spent so much time building this site in WordPress, it is not an option to now switch to Joomla. But creating several hundred unique user roles is not appealing. Can anyone tell me how I might be able to imitate groups in WordPress?