the four of us just clicked... how rare is this actually?

so we met a couple last month at a meet n greet in dublin and it was the strangest thing... all four of us just connected like wed known each other for years. ended up talking til 2am about everything except sex really, then went back to theirs and it was the best night weve ever had in the lifestyle. since then weve seen them twice more and theyre becoming actual friends not just play partners. is this normal or did we get really lucky? we've been in LS for about 3 years and met loads of "fine" couples but never this... wondering if its worth chasing or if we should accept it as a one off and keep our normal rotation going