How can I separate data for multiple customers?

I want to set up a Drupal site where a group of Customer Admins can manage the same type of data (content types) for different customers. I considered a multi-site setup, but this seemed a bit too complex.

Here is what I want to be able to do:

• Site Admins can create content types, modify the structure of the site, etc.
• Customer Admins can log in and add content for any customer (but not create content types)
• Customers can log in and read data that is only related to them, but not for other customers.
• When different customers log in, t开发者_JAVA百科hey should be able to be directed to a branded landing page for their company.
• All users log in to the same URL (not separate domains or subdomains)

I've looked into a number of different modules, but I'm not sure which one(s) would be best for my purposes. Any ideas?

Update: I appreciate the answers suggesting different modules to look into, but as I stated above, I've looked into a number of modules, but because there is so much overlap, I'm not quite sure which one would best suit my needs. I've looked into: nodeaccess, spaces, Organic Groups (og), subdomain, domain, feature, and context. The answer I'm looking for would have more of an explanation on why one module would likely serve my purposes better than others.

---

The Spaces module provides most, if not all of the functionality you're looking for.

---

You might also want to look into Organic Groups