@kyleheney What I’m doing in my example is what you describe in your Edit2. Have an “admin” value in the sheet, create a multiple relation to an admins sheet that has the same “admins” value, then create a lookup that pulls all the admin emails. You have to make sure the admin records are in rows instead of columns. You would only have one email column in the admins sheet.
In my screenshot, Email 1 is just a single email column of the row owner. Lkup-Admins is a lookup array of multiple values from a sheet that has multiple rows.
Filtering by signed in user works great with an array created from a lookup
I’ve had a problem in the past with what @Robert_Petitto is saying. I wasn’t able to successfully do a lookup into an array to create a super-array inside the lookup.
I haven’t tested this, but I’m assuming this may be the issue you have had with doing a lookup into an array column on the related sheet.