I'm guessing that the tower at Armstrong International is unmanned.
Shouldn't be a problem. If the weather is VFR (better than 3 miles vis and 1000' ceiling), the helos can operate on their own without talking to ATC. I'm sure the class B or C (whatever NOLA has) airspace is not being enforced.
The helos would have a common frequency to talk on so they can let each other know where they are and provide their own separation and traffic control.