See if your friends are in a voice channel you have access to

It would make it easier for me to find and join friends if I could see if they are already in a server/channel that I have access to. Some of my friends share many servers with me and it is a bit of a pain to click through all of them and scroll through the channels to find them. 

Sometimes I think I have seen something like this, but it does not seem to appear in all situations…