Redundancy - huge discrepancy

I work for a large national company and like many others, in the background there is often talk of redundancy.
For several reasons the thought now holds some appeal so I started to look into finances etc.
My department would be paid far less than others to the tune of approx 25000 if it comes to fruition...regardless of personal situations this is grossly unfair.
I've made contact with the union about it but I'm curious if anyone else has heard of or experienced this?