Not possible to rename (i.e. give shorter name) to group conversations. I can only see the name of the first group chat member that makes it difficult to distinguish it from individual chat.
It would be good to press-and-hold the conversation title and have rolldown menu with name change option.
you can just click on the names and change it.
You can set a topic/name a chat by opening the chat, tapping the three dots on the lower right corner and then tapping "set topic".