I am not a professional MEP programmer, and my experience in that area is limited. My main expl;oration into that area was the research and implementation creating a rolling offset:
Based on that, afaik, there are two ways to approach this:
- Place the pipes only and connect them; fittings will be inserted according to the routing preferences
- Place the fittings only and connect them; pipes will be automatically generated and inserted
For the situation you describe, the second option seems more appropriate.
Good luck, and looking forward to hearing how it goes.