Different sites

Hello,
I was wondering if someone could help me out with this issue I’m having.

I have a cafe with three different locations.
I have installed multisite, and create one site for each location. Total i have four sites in the wordpress installation. 1 homepage (where i put three images of location the user can click on to be transfered to the location they want). Each site has different main menu setup. I also linked to each site in the footer.
I use the same theme on all sites, and have set ut different menus and content on each site.

My problem is;
1. When I click at one of the location from the home page, I get transfered into the new site, BUT the header main menu don’t change.
2. it also happend when Im at a site, and click on the link to another location in the footer, the url get changed, but the header main menu on the previous page will remain even if the url is updated.

Does anybody know how I can update the menu automatically as well?

Hope someone understand my question and I appreciate all the help I can get.