Simple way to keep 2 sets of data represented fully in a 3rd?

Sheet1 - Names and phone numbers of a group of people that changes regularly, but must be updated with deletions and insertions in the list

Sheet2 - Exact same idea, but different group of names and phone numbers, also changes frequently

Sheet3 - shows all the names and phone numbers on both Sheet1 and Sheet2

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Currently, I am manually inserting references to Sheet1 and Sheet2 onto sheet3 which is clearly a headache. I was hoping for some formula that would watch Sheet1 and Sheet2 and update Sheet3 on its own as entries are added and deleted on the first two sheets.

Is there a simpler way than the manual references I currently chase all over the place? Sorting on Sheet3 isn't critical, but would be nice, too.