I don't think this is exactly what you are looking for, but I think it would be a lot simpler processes than what you are doing.
If you've ever sliced a 3D solid, there is a command in Fabrication (SLT) that does something very similar. You should be able to draw a (line) cutting plane that crosses the pipe you want to chop off. Run SLT, select the line, right click to close selection and a dialog will pop up featuring all the relevant items crossing that plane. Depending on what kind of system you are running, this could do precisely what you want, but I assume you are using a more sophisticated service than PExPE connections. So, on a copper system you will see it cut the pipe and add couplings at this lines location. Maybe windowing the excess and deleting it is close enough for what your doing?
An alternative (more precise method) is to add a zero thickness joint into your services that allow a PExPE connection and give it a specific button code that you can target with the SLT dialog, but I am not fond of that idea.
