I'd just hang the one feeder in the place that seems most popular with the birds--doesn't probably matter which one you hang--then just use the bee guards off the 'retired' one to protect all the ports of the one you hang. If the birds start defending the remaining feeder too fiercely, though, you might have to hang the second one back up in the end, anyway.
Are your feeders in full sun? We seem to have less trouble with hornets when the feeders are in a shady spot.