2 Bonded Pairs being aggressive

Question
We recently adopted 2 bonded pairs of cavies from 2 different organizations.  We brought the female bonded pair home first and then the 2 males.  Their cages are side by side but they can not make any contact.  When we take one cavy out for whatever reason and return him or her to their cage their "mate" teeth chatters and does the low growl and then the angry mate will chase the other around the cage.  If we approach the female enclosure first to give greens or replenish hay the males seem to get angry or be jealous.  

Is this normal?  Should we put the cages on opposite sides of the room from the other?  None of the cavies are spayed nor neutered so they will not be making contact but of course they know the opposite sex cavy is near.

Thank you in advance for your attention and help with this.

Answer
They can smell each others hormones hence the reason for the aggression. There is naturally disputes when the opposite sex is near.
You are best to get the males neutered to reduce the anger as it is the testosterone hormone that is causing the upset with the males and they are the two that are most likely to fall out.

It is a good idea to move the housing totally away from each other
Also make sure you wash your hands in between handling the males and females.