Lets try this...
There is 4 members in a party.
The checkbox seems like a good idea. Instead of it kicking the leader, the group could move without him. It is like this...
Checking the box means that those members would go off to another party and still stay together while the leader is still there.
First person checks the box.
Second person checks the box.
Third person decides to stay with the leader.
Both the first and second person would go off into the depths with each other. This could be another means of "solo" but it is a group that part away from the leader.
~An idea I made out of this forum post.
What was the point of this if your comment was already in the original forum