This is a bit confusing, I believe. Currently only the LoN set is marked as viable for group play, while it seems to be a consensus that Archyr Firebat is also very much viable on group play and only might be overtaken by LoN at high end pushing. Also in his recent reddit post Deadset marks Archyr build as viable for group play.
Currently, the set here is marked as only for solo play and there is no mention of group play in the whole guide. I think it would be nice to clarify those things