Not sure how many people would want this, maybe not that many. Depends on how many people use the groups, I suppose... Or would be more likely to use them with this feature. People post things in groups that they will later want to remove, for instance if whatever link is no longer useful. I suppose I'd also say it would be nice to be able to make more people admins in groups so it isn't just one person having to invite however many people.
I think it's a very good idea. That said I'd label it low priority as actual game play improvements should come first in my eyes.