Mail Merge - two or more addressees in one letter

[FLRob22]

How do I use Mail Merge to send a form letter addressed to two or more
addressees? What I want to do is set up the form letter like this:

First Addressee Name Second Addressee Name
1st Addressee Address 2nd Addressee Address
1st Address City-State 2nd Addressee City-State

I also want to print envelopes easily by highlighting the Name, Address,
City-State, etc. and then click on tools, envelopes, etc.

Any ideas?