Best Way to Relate Feature Classes

So here is a little background on what I am trying to do:

I have a point feature class called Lift Stations. This feature Class has one field...LS_ID. My other feature class I have is called Pumps. This feature class has two fields... LS_ID (for the lift station it is related to) and Pump_ID (either pump 1 or pump 2). At a lift station there are typically 2 pumps, sometimes more. I want to be able to click on a lift station and see that there are 2+ pumps associated with this lift station.

Since I want to publish this to ArcGIS online and be editable, I wasn't sure what the best way was to go about this. The field crews need to be able to edit the data, but want less clutter on the map. That is why we want it to just show the lift station, but when they click on the Lift Station point, I want them to be able to edit the Pumps data.

Any ideas for this?!

Thanks!!

Laura