Please check
http://manuals.sharkrf.com/openspot2/en/dmr-usage-notes.html
Talkgroups and reflectors are network features, they are completely handled by the network and not the openSPOT2. Please contact BrandMeister Network support if you have TG link issues.
Also keep in mind that the BrandMeister API sometimes does not report linked talkgroups correctly. If you key a TG then it will be dynamically linked automatically by the server, even if the API server does not report it (the API server is where your browser downloads linked TG info from).