first of all, how big is the tank?
That makes a big differance for multiple reasons. in too small of a tank male gouramis WILL bicker amoungst themselves, even if no permanent damage(open wounds from bites) is done. Also, from the sounds of it, you have full size gouramis, so unless you have a 55 gallon or larger tank, expect the battles to get worse.
If you do have a 55 gallon or larger, just ignore it unless one is being cornered and is unable to eat or move because the other has it pinned, or unless open wounds appear on one of them.
If you have less than a 55 gallon, take one of them back. if you have less than a 29 gallon, take both of them back.
Most gouramis sold in fish stores are male as the females tend to not have the brilliant colors the males do, most stores cant even special order females, so most of the gouramis you buy in the pet stores are all males...so, just like in the wild, expect them to get territorial and chase others out of their space or to wage war amoungst themselves.