Multiple Domains for SharePoint

I've got a single SharePoint Server.   I need to create multiple domains (subdomains) and I need to create a SharePoint site/site collection for each subdomain.  I need to ensure users accessing that SharePoint site is only available to that one subdomain, and not other subdomains on the same level.

I hope that makes sense...

Domain A
SharePoint A
|
|-> Domain B          Domain C         Domain D
     SharePoint B     SharePoint C   SharePoint D

Sooo... if a user is logged onto SharePoint B when they go to search for users from a Person or Group lookup they ONLY see users in Domain B, since they are in SharePointB site.  I'm running SharePoint Foundation 2013 to make it more complicated.