Combining antennas can be tricky depending on what each antenna picks up and how their signals will interact when combined. That said, if what each antenna will pick up is mutually exclusive of what the other will pick up, then you should be able to get away with something as simple as a combiner/splitter. Or you can use a rotator.
These 4 antennas, plus two more in my attic, are all joined together and I can watch any channel on any of 4 different TVs at any time...no rotor.
It is not guaranteed to work, but if you are lucky and your channels work out correctly, it can work wonderfully. As said above...post your TV Fool plot. Be sure to use your exact coordinates of your antenna location (per google earth) and your antenna height.
As always, run your TVFool plot and post your results link so we can see what channels are in play and where they come from.
I can't highlight and copy the info, so I'll summerize it.
All my local channels come from the same Azimuth True and Madn.
The distance for local channels are very close to 20 miles.
The signal goes from Pwr(dbm) -46.1 to 59.5.
Real channel the lowest number is 12 and the highest is 51. Real channel 12 is 2.1 here and a hard one to get. It is also the one with the highest Pwr(dbm).
WLS is another hard one to get. They broadcast on 44 mapped to 7.1. I get nothing on 7.1, but on 44.1 I get WSNS which says it's real broadcast is 45. In the chicago thread people are saying there is interferance and they expect 44.1 to get booted.