Dual iTunes Accounts Problem

[Moonloop]

I have 2 iTunes accounts , 2 different countries' iTunes Stores U.S./U.K. Is there a simple and reliable way to switch between them ? Option-Clicking iTunes does not alter the Preferences/Library/Advanced/Location tab or select each country's store automatically and they keep getting mixed up when it comes to syncing phones and iPads or trying to stream movies .

Both libraries are stored on different external drives connected to 2012 Mac Mini so it should be a lot simpler to select each one

Any one have similar problems ?

~M~