I want to create a workbench that accumulates the flowrate through a drainage wastewater pipe network which has some flow monitors in between pipes and some at branches. I want to accumulate the flowrate such that:
- The flowrate of a pipe leaving a branch (with no flowmonitor) is the sum of the flowrates of the two pipes entering the branch (leftmost diagram)
- The flowrate of a pipe leaving a flowmonitor is the flowrate recorded by that flowmonitor (middle diagram)
- The flowrate of a pipe leaving a branch that has a flowmonitor is the flowrate recorded by that flowmonitor as shown in (rightmost diagram)





