2 AppleIDs from 2 countries - Can I consolidate?

Is there such a thing as a global AppleID? I'm an American living in Scotland. I have been able to add country-specific apps from both sides of the Atlantic (had to create a UK AppleID to get UK-based apps) but I want to use the same AppleID for all of them.

For example, I am able to use my banking apps from US and UK...but I had to download them from the country-related App Store.

I want only one AppleID... is this possible?