Xbee two way communication, multiple modules

Hi.

I have question regarding two way communication between Arduino boards with Xbee. I would like to use up to 20 sets (Arduino + Xbee).

One master module (coordinator) should be allow to send and receive data from each module as shown in Picture (20150319_200740).

Example:
M ( Master)
Sn (Slave)

M1 receive data from S1
M1 send data to S1

M1 receive data from S2
M1 send data to S2

and so on…

Is it possible to do this in that way? Communication not need to be fast. Does Xbee modules are suitable or I should use different one.

Best regards.