Thriller piece- group placement

I am currently working between two separate groups. Firstly, my original group- myself and Matt. Matt is possibly leaving the media group soon and therefore I have joined another group consisting of; Jamie, Tom and Jack. I have began planning a thriller piece my original partner Matt, but I have also been contributing to my potential second group. If my original partner leaves then I will move into the second group permanently. However at the moment Matt is unsure about whether he will be leaving soon or not.