What’s the best way to reference a unique ID from another protocol / namespace that doesn’t have a canonical url?

Obviously I am thinking about podcast feeds / episodes for which the guids (unique ids) are supposed to be honoured by hosting companies when you switch providers.

Another example might be book IBSNs.

Wouldn’t it be useful to have a way to tag these entities according to these agreed IDs that aren’t tied to any one platform? (as opposed to just putting in platform specific links that might not work in the future)

Wouldn’t it also be useful if these tags could apply to any event kind so that nostr users could find all the activity related to a given podcast episode / book - whether it’s a comment / long form text review / live stream with the creator of the original content?

What do you think the best approach for doing this is?

(my reading of NIP-32 was that this was what it was for but maybe I’m wrong)