XBee Point to Multipoint Conceptual Design

I am using a Series 1 Xbee 802.15.4 to set up a point (coordinator) to multipoint (end devices) network. Each end device will need to be able to send some data back to the coordinator, but not all of them at the same time.

The end device should have the ability to change their address so that multiple end devices are set to the same address at times, and at other times they aren't. For instance, if I have 100 Xbees, I might want to use up/down buttons to change the address of 62 of the xbees to the same address so they all receive the broadcast, then the rest of the Xbees to a different address, etc. Is it even possible to have that many xbees receive a broadcast? Can 100 xbees be supported in such a network?

I want the end device addresses to be able to dynamically change, meaning that after I have configured them in XCTU with their 16 bit address, I want to be able to use up/down buttons to change their address up or down while they are on. Is this possible? Or maybe I could have the up/down buttons change an address in software rather than the XBees physical address and then determine if it should reject or accept incoming data?

Thanks in advance!

Is it even possible to have that many xbees receive a broadcast?

How many people can listen to a radio station at the same time? Why would you imagine that there is a limit?

Is this possible?

Up/down switches connected to what? Anything that X-CTU can do, an Arduino can do. I'm not sure that what you want to do is smart, though.

Are the XBees connected to Arduinos? If so, changing the ID that the Arduino knows has nothing to do with changing the address of the XBee it is carrying.

Yes, each Xbee will be connected to an atemga16a microcontroller. I want to use two push buttons to change the "address" of the xbee it is carrying. The thing is, i dont know if it is wise, or even possible to change the physical address of the xbee that way or if I would just change something in the code so that the micro controller ignores anything without that ID tag...if that makes sense.

If there is an Arduino at each node, the XBee's address should be left alone. The XBee will receive whatever data is sent over the air, and pass it along to the Arduino. The Arduino is the device that needs to know anything about an ID. It is the thing that needs to make decisions based on ID. So, it is the ID of the Arduino that you want to adjust with the switches.