How to configure star network topology for Xbee

I am using Xbee S2 module.
I want to form star network in transparent mode with a coordinator and around 20 end devices. So as per my knowledge i program the destination address(DH and DL) of all the nodes to coordinators address using XCTU and a star network is it correct?
Is there a way i can get the coordinators address from the packet received in transparent mode? How do i program it in DL and DH of the end device without using xctu in transparent mode?


No you do not need to do that at all. Just set one as a Coordinator and then power on the other nodes as End devices. Just know that depending on which version of the S2 you have, you may need to set up one or two routers for that many sleeping end nodes.

ok. How do i make sure all the end nodes will connect to one particular coordinator not some other in the nearby network?
And why would i need a router? i am not using mesh?

An S2 only supports up to 10 end devices per parent. Your 20 end devices exceeds the max number of end devices it supports.

Any suggestions for an ideal network setup which can support maximum devices?

The modules you mentioned are Mesh based products. It can only support up to 10 sleeping end device children per parent (Coordinator or Router). In order to have up to 20 end devices, you will need to have 1 coordinator with 10 end devices associated to it and one router with 9 additional end devices giving you a total of 20 devices.