Do you mean:Folks, I have both a UK and US Apple ID. Is it possible for me to have 1 user ID for my UK account and 1 for my US account on the same Mac?
2 separate user accounts.Do you mean:
Two separate user accounts, one signed in to US and one to UK…
or…
One user account with primary Apple ID signed in to (say) US with a secondary Apple ID signed in to UK?
Be aware that Secondary Apple ID accounts can only sync Mail, Contacts, and Calendars.
I would think first method wouldn’t have a problem with US/UK, less sure about the secondary account route.