While the signals from both markets are receivable for the most part, one antenna will not be able to provide simultaneous reception of the weaker signals from both directions.
For maximum reception of both markets, point a Winegard HD7698P + RCA TVPRAMP1R preamplifier toward Indianapolis. Aim an Antennas Direct 91XG or DB8e + TVPRAMP1R toward Fort Wayne.
Combining the two antennas is theoretically possible, but would be cost prohibitive given the needed tuned filters. Instead, consider one of these options:
http://forum.tvfool.com/showthread.php?t=2882