A bigger group differents paces

The Tuesday group of running is become larger. Now it's 4 person group, what is nice. The problem is that the 4 of us have different paces. To try to solve this I bought a bike to my wife, and so, the two girls today shared it. The result is better, but is not good: my pace still to be greater! When I run alone with my wife it's very good, I run at the pace I choose and she follow me. With the bigger group we need to find a better solution, maybe create to groups...