this project hooks up OpenSim Group chat to matrix rooms with invites. AV profile pics/names/uuids show up in matrix room and matrix name/etc show up in OpenSim chat. all users share the integrated chat room. Matrix view (using element web client, but you can use any Matrix client, ie phone, etc)
https://gyazo.com/714e862c670dd0fcdeff5566477838bd

here's the first commit comments appreciated! https://codeberg.org/fionasweet/opensim-matrix-bridge