This is a really simple keybind and it does exactly what you imagine - Evacs my group! I have it bound to Ctrl 2 and I only use it all the time when I am in danger or just want to get near a specific zone line/safe spot in a zone. I have a Wizard in almost every one of my box groups and they get the AA Exodus extremely early on which is exactly what I use to Succor my teams.
I just plop the ability down on the hotbar - I don't put it into a macro. Druids also get an AA called Exodus too - if you don't have a Wizard you can use a Druid! One other thing that's worth saying about this Keybind too - don't sit there spamming it. Once you Exodus if you keep spamming it then you'll Exodus again immediately after you finish loading as another one of your character's fires off the ability. It can be pretty annoying!