Find routes learned from two particular neighbors?

So, outside of scripting, is there any way anyone knows that can let me compare the routes received from two iBGP peers in IOS-XE that will let me see any prefixes advertised by both?

My use case here is I have to reverse-engineer and evaluate the impact of removing a bunch of seemingly random iBGP adjacencies with weights and other attributes applied to them.

i.e.

!R1 router bgp 65000 router-id 1.1.1.1 address-family vpnv4 neighbor 1.1.1.2 activate neighbor 1.1.1.2 weight 300 neighbor 1.1.1.3 activate neighbor 1.1.1.3 weight 75 neighbor 1.1.1.4 activate 

when, in fact, a cursory manual investigation doesn't reveal *any* obvious prefixes that would ever be advertised from any pair of the neighbors. So either there isn't any and these do literally nothing now (and possibly never did), or they *are* impacting some small subset of prefixes advertised from two or more of the peers and I just haven't identified them yet. Can you guys think of some way to identify that set of prefixes, if it exists?

EDIT: I should clarify that we want to assume that there's too many prefixes scattered among too many RDs for a human powered manual scrub of the routes is out of the question.