They will have the same text for each letter, so all they have to do is print it, address the envelope, and post it. Takes no time at all.
Au contraire mon ami.
First they need to zoom in at 8:45 A.M. to visit, drink coffee and at 9:00 A.M. have their "meeting" for serve-us and get the days marching orders. Then they need to yak with each other for maybe twenty or thirty minutes about how many letters they have written, are writing, and going to write. Then go to the kitchen and get another cup of coffee. Then read the letter that they wrote months ago and have been running off on the copier, just to refresh their memory. Then make the first copy for the morning. Then re-read it and sign it. Then print the envelope. Then get a second cup of coffee. Then put the postal stamp on the letter. Then yak some more for "break" with their zoom group. Then repeat the entire process two or three more times. By then it is noon. Grab a sandwich and go to the post office to place it in the mail. Go home. 1:00 o'clock and an easy four hours serve-us time.