The best group that I have ever been a part of was super forced. We were literally forced to spend hours together, add each other on social media, have a group chat, meet up for lunch or drinks. We HAD to spend so much time together and forced to become friends and that is why we were such a great group. We ended up becoming friends and caring about one another and liked the assignments we had because we got to get together and hang out.
The best thing to do in a group is communicate and be honest, one week if you are too busy maybe a group member can pick up some slack and vise versa the next week! Caring about others is key.