What is SDD?? As soon as Im told Ill prolyl know...but anyways...
We used to get heaps of group work assesments when we were in the junior school, didnt bother me really, until I got into groups wher it was only myself and my bestie doin all the work, so to fix our group members, we would only write the names of people who actually contributed to some extent. That way, there was someone who didnt have something done and they would always get into trouble off our teacher. The teacher may then ask "Why wasnt *insert name here* 's name put on the assesment?" I would always say "Well, maybe if they had contributed something maybe their name would have been on it..." always works/worked.
I always found working in pairs to be so much better, unless you were paired with someone you do not get along with, because then there is no communication, and they end up chatting to their friends, while you get stuck doing all the work...and its far easier for them to realise their name isnt on the page when you hand it in!