Right now, the only way I can think to do this is by combining all surveys into one so I only have one feature layer. However, I don't really want to do that because that would make for one gigantic survey. It would be much better to keep the surveys divided.
One option might be to combine two of your hosted feature layers through a join with the output as a view: Join Features—ArcGIS Online Help | Documentation - this would reduce the number of selectors needed.
You can also have one service (for use in the selectors) and different surveys with a selected group of questions. E.g. you can have fields in the service that don't have corresponding questions that write to them. See the doc on this here: Use Survey123 with existing feature services—Survey123 for ArcGIS | Documentation
Hope this helps,