Your current mentions method will be good I think, the same method works for all kinds that I have seen; the mentioned user is tagged with "p" tag.
Kinds within the 5000-7000 range are defined with NIP-90. Within NIP-90 "p" tag defined as:
"p: Service Providers the customer is interested in. Other SPs MIGHT still choose to process the job"
That's the kind of mention I'm looking to work with.