Help to separate groups

Hi everybody.

 

I'm responsible for a selection of new members. I want to make everybody have the same chances, working with different people.

My idea is to ask for the areas send me what projects they need, with the difficult and how many people need. With thoses information, randomly allocate everyone.

I want two criteria: not repeat the same group and do not have differences in total difficult exposed. 

 

Can someone help me? I don't know how to use the Solver.