Convict cichlids will breed with Firemouths, Blood Parrots, Red Devils, Midas cichlids, Texas cichlids, and i'm sure i've missed some names. So maybe they aren't just the "rabbits of the cichlid world" they may very well be the
You say you have texas cichlids and they may be a pair?
Well, if they are a pair and you want to "crossbreed" don't split them up and see if one crosses with the con, because that's mean IMHO.
But if your texas cichlids tunr out to be two males then you can take one and cross it with your female con.
Oh, and do you have a description or any pics of this "other cichlid" that you also have??