There is nothing wrong with dividing up the work activities as long as they are sequential. What I mean by that is:

1) Initial Dirtwork - level area
2) Underground Plumbing - excavation, installation to code requirements
3) Concrete - forming, pouring using building supplier's setting plan and code requirements
4) Building erection - everything including doors, windows, insulation, etc.
5) Interior plumbing
6) Electrical

If you spread this out you can avoid the hassles of contractors running over each other. The critical contractor is the concrete contractor. If he can follow the building supplier's drawings accurately you are home free. Just my