Right, normally when an invasion goes down, a group starts up.
These groups are nice because it helps you determine where all the action is happening.
The problem is if you're a tiny bit late, the group either fills, or you aren't at the right rift to join.

Could we get a "Join global group" button?
The group would have no leader and disband automatically when the invasion is over.
There would be no max amount of people that can join either.