Many groups have figured out that when you launch an instance from the VRChat website you can change the instanceId= in the URL to something specific such as GroupName and then the instance will show that in the instances lists. Many users have figured out to look for specific groups in the lists this way as well. However, since 1431 has come out the instances are pre-closed. If GroupName was made one day and then everyone leaves it closes. Then, when that group makes the instance GroupName again it will stay closed. People from the group will join but nobody will see it in the instances lists.