If you are using more than two providers for the same service or amenity, you should see about paring it down to no more than two (it is understandable to be using more than two providers if your communities are spread out geographically), however, you may want to see if one of your current providers is able to accommodate multiple locations and/or has expanded their territory.
By reducing the number of providers you should be able to get better pricing, improved customer service and many other benefits including a reduction in the amount of time and expense spent processing and paying invoices.