The houses are based on nations.
Its a good enough word.
Short answer: Yes.
Long answer: Yeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeees.
I'd guess Interspace.
As in, Interspace Commerce.
But seeing as just the word "Interspace" is pretty much associated with IC like 100% of the time, it could be difficult to work the word into anything without making it seem like you're talking about the company, not the four houses.
In that case, you might just make up something by yourself.
Or make a topic asking people their opinions, and choose one of their ideas.
Which is what you're doing here.
Carry on.
Intersteller 8-|
Better yet, Interstella
Since a nation is a group of ethnolinguistically homogeneous people, yes, international does apply.