As
blakcloud wrote, a hitch-mounted rack will generally pivot downward to allow hatch access. Even with a couple bikes mounted, you're taking advantage of leverage, so it's not that hard to move the bikes out of the way and then back up again.
When I was buying a rack, I found it helpful that the shop guy had the same one on his car -- we just went outside and I got a demo. If you go to a large shop, someone will have a rack on a vehicle outside and give you a demo - and then be able to explain the differences with other models. Pro tip: then buy the rack from that shop.