Google Analytics with subdomains and aggregating data

I am building a network of sites that have a single main domain at example.com and several regional sites that use subdomains of the main one, such as:

• example.com
• site1.example.com
• site2.example.com

I have two goals for setting up Google Analytics with this network, but I'm afraid it may be contradictory based on how GA works:

1. I want to give each subdomain its own GA account so that managers of the regional sites can see their stats, but not the other regional sites.

2. I want to be able to aggregate all of the regional site data with the national site data for executive management review.

While it's pretty easy to set each of these sites up with a Google Analytics account of their own, I don't know if this is the right way to go.

Can I satisfy the requirements of goals #1 and #2 with Google Analytics? If yes, how can I best execute it?