No single definition of "polyamory" has universal acceptance, with the Oxford English Dictionary having widely divergent definitions for the word for the UK and US versions.
If they are members of the group you know that are at least poly-friendly.
While polyamory and BDSM/ kink are not related there is a big overlap in people who are involved with both.
Fetlife has an option where you can be polyamorous and add all your relationships, whether they are kink related or not.
I prefer meeting people at parties far more than being set up with someone on a blind date, but a lot of polyamorous people have luck with both.
Fetlife is a kink and BDSM site where you can connect with other kinksters.