How to Nest two looks

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I have two separate looks that i am trying to combine into one. The first look gathers a set of emails that are associated with a specific tag. The second look then takes these emails and gathers all other orders that do not have this tag, but share the same email.

I’ve tried creating custom calcs, measures, and even played around with merging, but no luck.

im still learning Looker, so any advice would be great. Thanks!