How we can forcefully connect end device to the router

Hello,
I am using XBEE PRO S2C modules, where i want to forcefully connect end device to router.How can I do it. It should’nt change the path once connected.

Set the NJ value on all others nodes to 0. Then set the NJ value to FF on the desired router. Then power on your end devices and let them associate to the desired router.