ゲストハウスの当番だということで、郷田さんと熊沢さんがゲストハウスまで案内してくれることになった
I'm often troubled when I see ということで in the middle of a sentence. Looking at this sentence makes me wonder if there isn't some kind of "because" or "since" meaning implied with ということで, but as I'm not sure I'd like your opinion on it.