api for charms: how to export links to entities

[seefeldb]

a categorizer might export an array with ids, and those ids match something on their inputs. but a next charm using those ids would have to import both, know how to match it, etc. -- can we instead via schema declare that these ids are the same as from the argument and then for other charms rewrite the result to expose the entities themselves instead of just the ids? or at least know to link to both?