Membership plugin & site architecture

I currently am setting up 2 sites. Site 1 is for my coaches (sales people) to use to access forms, training, etc... Site 2 if for the customers who access a set of pages which is a schedule of things they do.

Currently i have 2 wordpress installations setup under 2 different domains. Now that I am going to use the Membership plugin would it make more sense to migrate and use 1 site for everything and control access through membership? right now my coaches will all have their own accounts and I was going to use a single generic account for the users. In the future this may change but after thinking I thought it might not be the best idea to manage 2 sets of members.