Google Flights API (QPX Express) - Multiple Cities of Origin or Multiple Dates of Origin

Does anyone know if there is a way to send multiple origin cities on a single request? Or search multiple date ranges for a single query? I'm looking for the cheapest flight for a certain amount of time (I have flexible holidays) and I live between two mid-sized airports and don't really want to send multiple requests for each one. Is there at least a way to search for multiple origin airports on the same one? I've tried using my destination as a clean string as well as a list.

Things I've tried:

'airport1, airport2'

['airport1', 'airport2']

      

        
        
        
      

    

If airport1 and airport2 are of course the airport codes for the ones I'm looking for. If I use the list method, it just looks for some kind of first, not the second.

I would just submit requests, but it's slow and costs $ 0.03 per pop ... which adds up quickly when searching every 2 hours!