How can I identify the router through which the message is passed?

Hello guys,

My question question is: how can I identify the router through which the message is passed?

ED -> R1 -> C
or
ED -> R2 -> C

If my ED send a message in broadcast mode (DL=FFFF), how can I identify the router which relayed the message to the C ?

Thanks in advance

It is going to be which ever router the End device is associated with. IE it’s Parent.