End Device to Co-ordinator via two routers

I’m completely new to XBEE and want to create a sensor network like the following:

Co-ordinator -> Router 1 -> Router 2 -> End Device 1 & End Device 2

Since the End Device 1 and 2 are out of sight from Co-ordinator hence the two routers are absolute necessary. I have 4 XBEE S2C Pro modules to complete my network.

If anyone can point me in the right direction it will be appreciated.