I have been ponding ways to promote grouping/LFMs.
I am sure someone must have thought of this before, but if not...
How about a 20% boost for completion with a full group? (can negotiate boost number)-
6 people in group - extra XP-
Hires don't count.
The XP bonus has to be big enough to offset a death of a member / PUGGER and a little extra to make up for what would generally be a slower completion.