Its an alright way to feed them, but you need distance from your hives. I usually put community feeders at least a hundred yards from the hives, whether I'm feeding sugar water or honey.
Or locate the community feeder near a current source of forage, ie in the orchard, near blackberry briers, amid the clover or dandy lions, etc. If using a forage source to locate your community feeder it can be done successfully within 50 feet of the hives. I know because I have all of those things within 50 feet of my bee yard and I only have to move the community feeder 10-20 as the forage cycle works its way through the year.
I've experienced much more robbing amongst hives when feeding an individual hive internally over feeding them all. My approach is to feed those that need it internally and all of them with a community feeder. Since I started that I haven't had a single case of robbing, even with the close proximity to the bee yard.