Leon of After Nature has an excellent post discussing internal vs. external relations. Of course, like many Americanists, he transforms the dualism rather than accept it.
Both of us have had many discussions with interlocutors, both in person and online, that are utterly baffled when we talk about relations. I think the problem is, at least for me, that I constantly under-estimate how radical my own perspective per Americanist thought is for analytic philosophy. I suppose continentals get the gist fairly quickly, since Americanist and (post) Heideggerian translate easily, but both of those groups are in the vast minority.
I am mostly interested in the temporal relation understood in its causal aspect.