I just had an odd thought.

If we had a special widgit ie the flag that controlled whether certain ships could be purchased while it was in nation space.

Serco - scp
Itani x-1 or valk
Uit - Moth?
Grey - Greyhound

Each ship could only be purchased while the flag was in the related space. The flag cannot be docked with or destroyed. Any ship carrying it would be marked as ? KOS?

Anyone care to flesh this out a bit?