Academic project

I am analyzing a water distribution network having 689 no. of pipes. This is purely academic purpose. In our institute, we are having an academic license with the limit of 250 pipes. Therefore I am unable to run entire network. To overcome this problem I am created 4 selection sets. Each selection set having less than 250 no. of pipes. To run entire network how to proceed? How to give Boundary conditions to these selection sets? After giving boundary condition how to proceed? To run an entire network with the help of selection sets how to proceed?