Here`s a suggestion. Just like you can have an ignore list on pms, how about a feature where if you`re selling stuff on the market you can have a list of up to (say) 20 empires (if you so choose) to whom you will not sell to.
If they`re trying to buy on the market and it`s yourstuff, a pop-up/or different screen can come up saying (along the lines of) "nope, you`re a reject -- would you like to buy the same amount of stuff at the next price"
What do ya think? e.g. a fed can pull together and boycott another fed. In an UW, sellers can boycott most of the UW`s supporters to prevent `em buying up minerals (hence allowing newbs to build up and attack etc).
A
archaeoptyOP