A Rebbi of mine in yeshiva said in the name of Rav Ruderman z"tl who referred to a Chazal that a person should ideally try to marry someone from the "same מבוי, if not then the same שכונה, and if not then the same עיר," explaining that the less differences there are, the easier the adjustment which is required for marriage.

My question is where this Chazal is located? (My Rebbi wasn't sure, although I was wondering if it's Yalkut Shimoni 391:14)