Let's say you find someone you like. Are those the conditions you want to impose on a new relationship? Are you looking for emotional involvement or "just sex"? Why not become involved with friends you already know?
Sometimes "rules" designed to "protect" the existing relationship(s) fall by the wayside when you realize you are now "in love" or when you want more out of the "new" relationship.
I'm not saying that what you describe "is not" polyamory, but I don't see it as a sustainable pplan for the long-term if you are looking for more than "just sex". And, if you ARE looking for "just sex", then, no, it isn't "polyamory".