Discovering Xbees in a Mesh Network (Arduino)

Hi everyone.

First of all,excuse me if i misunderstand something. Im a spanish guy.
Now Im working on a project that includes XBees modules, connected in MESH of one Coordinator and some routers (API mode all, same PAN ID). Im using AndrewRapp's library to program de devices. I was be able to make communication between Coordinator and a Router, just setting the Router's address in the Coordinator:

XBeeAddress64 addr64 = XBeeAddress64(0x0013a200, 0x40a1f246);

Later on I changed the code a bit and I tried to send a boradcast:

uint16_t addr = 0xFFFE

So any device in the mesh can get connected to the Coodinator.

But what I would like to discover how many devices are in the mesh, I mean, how many Routers are attached to the Coordinator. For example, If Im only working with one router, the coordinator code would tell that there is one device found. Two if there are two routers, etc.
┬┐Does anyone has a clue? I have already done a big research and I haven't found anything yet...