Can I set this up so that members subscribe to optional, multiple components?

I am looking to sell a membership subscription with three levels, for website upgrades and support. However, I want to provide an option for members to add support for multiple sites, to each account, at a price per site.

Can I set this up (and how would I do that?) so that each member signs up to a level of support (for their site), and then adds one or more additional sites to their account, at a price per site (or bundle of sites)?

I hope the question is clear. Let me know if I should elaborate.