I've just updated all stores to automatically show banner links to any sites you have listed on UMD. Nothing for you to do, as we're already linking to your sites now on the left panel. But if you wish to remove any of the banners, just hit up your Store Setup page and un-check them.
This is part of an ongoing effort to support sites outside of UMD... I don't want UMD to be a dead-end, including the individual stores. It should be a tool for discovery of what's out there. I'm open to suggestions.
M p.s. The left panel is hidden on mobile; For that, I'll add the banners on a separate page later.