In order to reduce the interference you could select an antenna with a null at 123 degrees to reject 21 and 23. The popular DB8e is about 23 db down at 123 degrees at those channels. (the 91XG is similar) That's leaves about 14 db to filter out with a Tin Lee filter. The extra 14 db could also be achieved by placing the antenna on the side of the house so that the angle toward the stronger 21 and 23 is blocked by aluminum siding, foil backed insulation, or some other RF opaque material.
A pair of 91 XG's stacked horizontally and spaced 42" apart could also get channel 22.
http://www.hdtvprimer.com/antennas/ganging.html