Help with adding teams from other nations to domestic cups

[deelaswatson]

Hi,

 

I'm looking to make a domestic cup competition with "guest" teams from other nations competing in it (à la Scottish Challenge Cup from a few years ago). 

How do I set it up in a way that allows me to have teams from different nations without changing the nationalities or leagues of said team? I can only get it so that I can add team from one nation. I managed to get this to work a few years ago but can't figure it out/remember on this year's editor. 

TIA