If this is implemented, maybe have a custom marketplace option tick box instead, the dropdown for each option.
SH is now allowing Afternic, but the price has to be > 110% (including floor). I’m sure with the right coding it could be done, and when these domains are added there could be a tick box that selects them for a custom marketplace, and then allows override tick boxes for Dan, Sedo, Escrow, Afternic, GoDaddy Etc which can be disabled or enabled for each name?
It would take some trial to make it right.
The system could also scan the DNS to enable the option if the DNS matches the marketplace with exclusivity requirements. Then this field doesn’t show up on all the names.