I would like to know if there is a way to show underfloor piping without showing anything else from the floor below.
For example: Create a second floor sheet showing second floor plumbing fixtures and only show the sanitary lines serving the second floor that is located in the first floor ceiling without showing other items from the first floor.
1) You could try using the Plan Region, but it is rather buggy with MEP.
2) Set the ViewRange/Bottom and ViewDepth to the same value to include the Sanitary pipe below the floor you are on, then TAB select the objects to hide, right-click HideInView.
Look through past messages on showing 2 views on a plot sheet. Basic intent is to show the upper plan with the architectural walls and piping on and turning the architectural link off in the lower plan (thus turning the walls off on the floor below) and only showing the piping.
sounds like you should create (2) two seperate views w/ the VG set the way in each the way you want. Then drag them onto the sheet that you want.
I seperate domestic water from sanitary piping this way.