Closest I could get was
ClearCollect(AllEmails, Distinct(Data1, email), Distinct(Data2,email))
This have me 2 tables within a table with the correct data. Makes sense as Distinct returns a Result table. So I guess my question is how to reduce that down to one table with a column with emails for both Data1 and Data2?
I was able to piece it together. Included a separator between Data1 and Data2, and specified sortorder for each, and removed blanks created by trailing comma.
Dropdown.Items =
Split(Left(Concat(Data1, email & ","), Len(Concat(Sort(Data1, surname, SortOrder.Ascending), mail & ","))-1) & ",-------," & Left(Concat(Sort(Data2, surname, SortOrder.Ascending), mail & ","), Len(Concat(Data2, mail & ","))-1), ",")
Closer now, I used
Concat(Data1, email, ",") & "," & Concat(Data2, email, ",")
which gives me a string of emails comma separated, now trying to fit this into a dropdown.