Multiple Menus for Different Site Sections Which Share Pages

I am working on a site for a client that has two different locations under the same site. They are wanting to split it up a bit more and have two separate ‘minisites’ under the same domain. I already know that I can add some code to get a different menu to show on different pages in the site, but the problem is that a lot of the information pages are shared between both locations. Would there be a way to know which ‘minisite’ they have navigated to and in turn know which menu to display if it is a shared page?