Add an observation field type that resolves to the community ID of a related observation

[bouteloua]

Yeah. I just don’t quite understand how it’s different from the existing feature request:

@KitKestrel

11. not to require that all linked obs be of the same species - e.g., be able to link the predator and prey in an interaction (if they are both in the same pic now, & the pic is posted to 2 obs to get both organisms into iNat, the connection is lost (as far as I know), altho those would technically be one obs, but one still can’t get both IDs on the same obs)
12. be able to label the kind of link (growth stages of an organism, predator/prey, parents/chicks)