Entering command mode while other XBees are transmitting

Hello, I’m in an environment where XBeePros are transmitting almost continuously. I’ve found that an XBee will not respond to the ‘+++’ to enter command mode if another XBee is transmitting. It appears as if the when the XBee needs to see one second of nothing after the +++, that transmissions from the other XBees fill that blank second with characters, so that the target XBee won’t go into command mode.

I find this curious that the XBee would see an incoming transmission as something that would effect the ‘+++’ command coming from the host. Is there a setting or something that would solve this?