XBee ID DL settings for one-to-many communication

I have a setup with 3 xbees. One is serving as the main communication point, and talks with the other 2 (mod1 and mod2). Those 2 receive messages from the main xbee and send some back. They only talk to main and don't talk to each other.

The main xbee only needs to send a message ever to either one of mod1 and mod2, not both. So the messages directed to mod1 and mod2 are unique.

I now have this configured like: main: MY = A DL = B

mod1: MY = B DL = A

mod2: MY = B DL = A

I'm wondering if this creates issues because I have 2 modules with the same (MY) address.

Alternatively I could leave this address to the default 0 so it becomes:

main: MY = A DL = 0

mod1: MY = 0 DL = A

mod2: MY = 0 DL = A

Would this be better in some way?

I'm asking because I'm trying to troubleshoot some problems I'm experiencing which seem to be related to overloading the network somehow. I keep losing connections for short periods of time.