When gossip is enabled it automatically checks kind 3 and adds for example a contact's DM relays to the pool? In that case are those relays treated any different from others in the pool? Like they should be writeable only for posting private DM's targeted at the contact they were added for, right?
Discussion
It doesn't check the kind 3 but the filters or the events.
Extract the author/s and the p tags from filters/events and request the kind 10002/10050 (if not already cached or if expired).
Yes, every relay have some flags (the RelayServiceFlags). These define what a relay can do. For example, the automatically added (the gossip ones) will have the `GOSSIP` flag.