need help with a tricky WP problem

I am building a website for a franchise company and they desire a rather unusual setup. I hope someone can help me figuring out what is happening here.

lets say their main site is franchise.com

every other franchiser has to set up their own domain, I am working on franchise.co.za
they desire that franchise.co.za is redirected to franchise.com/southafrica.
franchise.com/southafrica holds basic information and custom links set up by the admin for that particular country.
I have solved this with the plugin called redirection, I am redirecting / to franchise.com/southafrica so I can access the dashboard and any URL I type in, just the root will be redirected.

Now they want to set up a webshop, which will be linked from franchise.com/southafrica/ to franchise.co.za/webshop

ALL WORKS SO FAR BUT HERE IS THE REAL PROBLEM:
on franchise.co.za if I log in as admin I am in my familiar wordress dashboard and all is well but ANY other user will be redirected after login to franchise.com/southafrica - so basically only the admin can actually use the dashboard. I even tried to use a plugin that redirect depending on the user role but even that doesn't work. All users except hte admin are being redirected upon login.

any ideas what could be wrong here? I'd be willing to share the login details so someone can take a look since this is still in development.

Please let me know if I didn't properly explain and I'll try again if needed.