They've got the Conference Committee thing wherein Senate and House versions of the same or similar bills are reconciled into single compromises. So they all work together at certain times. And that's just officially.
UNofficially, they all work together even more. Count on it. These are social animals. Their whole reason for being, while there, is to collect allies. Usually on legislation - seeking cosponsors, seeking votes of support, etc. They're not always IN chambers. Sometimes they're out in the hallways - where lots of other people are. People like constituents, staffers from many other Senators' and Congressmembers' offices, and there are those very other Senators and Congressmembers there, too. And they're not just in the halls. They're in the cafeteria where "Freedom Fries" were once loudly heralded on the menu. They're outside in front being interviewed by somebody. They're sharing rides. They're running into each other at airports and at cocktail parties. Hell, some of them even live together during the week before heading home for the weekend. This one is called "Taking Power, Sharing Cereal" about how Schumer and Levin (Senators) live in the same house with George Miller and William Delahunt (Congressmen) during the work week. Miller owns it and the others pay him rent. And you think they don't talk about work when they're sitting there at the end of the day sharing cereal or Chinese takeout and complaining about Schumer's lousy housekeeping?
http://www.nytimes.com/2007/01/18/garden/18roomies.html?_r=2&oref=slogin&oref=sloginYou bet they wind up together, House people AND Senate people, and doing business across the two Chambers. And their staffers do so, too, even more intensely. They're the ones apt to meet each other at the dry cleaners, the local markets, bars, clubs, workout centers, bike lanes, and taxi stands. They're the ones who are gonna lunch together or go get a drink together after hours, or run into each other in the halls and stairways. They do the scut work and they're the ones who actively interface even moreso than their bosses do. And that's even more effective, I'd suspect, because nobody's paying much attention to the staffers and underlings and secretarial people and interns, and unless they're Monica Lewinsky, or they're cute young male pages and mark foley is still lurking around somewhere, nobody knows who they are and nobody cares, and no big-ass marquee-name network correspondent is going to waste much time on those grunts when the point is to chase their big name bosses around. So even though it's quite true that it's the HOUSE that IMPEACHES, and the SENATE that tries on those IMPEACHMENT counts, neither Chamber operates in a complete vacuum, strictly isolated one from another. It's A LOT of under-the-radar schmoozing, and it's a BIG part of the way business gets done there. It's called cross-pollination, and there's TONS of it everywhere. Especially since everybody talks and everybody gossips there - about EVERYTHING.
And believe me, Biden's been around long enough to know who gets the ball rolling on IMPEACHMENT. It's who he's now actively talking to, and with what urgency, that's the main interest here.