Playing with friends is the best. Individually messaging 20 people when you're looking for a game is the worst. Is there a way to make a persistent group chat (you rejoin it after restarting Steam) or some other way to reliably communicate with multiple people over Steam?
Not sure is this would work for you, but id say to try and make your own steam community group https://support.steampowered.com/kb_article.php?ref=2092-QLZX-8453#create and then use the chat function in there.
Also, is suggest making it private/invite only if you JUST want your friends. I havent tested the persistence of this, but i know the chatroom will always be available...