So, I am going to start defining some type of Custom Feed event type. 

nostr:nprofile1qqsf03c2gsmx5ef4c9zmxvlew04gdh7u94afnknp33qvv3c94kvwxgspz3mhxue69uhhyetvv9ujuerpd46hxtnfduq35amnwvaz7tmjv4kxz7fwwajhxar9wfhxyarr9e3k7mgprdmhxue69uhksmmyd33x7epwvdhhyctrd3jjuar0dak8x6lmt90 has his version below, but I find it too complicated with the union/diff/intersection stuff. 

This is complicated by definition, but it would be nice to have a feed defined in Lume showing up on Amethyst. 

https://github.com/nostr-protocol/nips/pull/1181/files