[Glinda]

Examples:

Dear elderly people:

Thanks for retiring to Florida thus making the roads in the other states safer.

~~Other 49 states

Dear Other 49 states:

Please stop sending your old people down here. We're full up.

~~Florida

Dear Florida:

If we up and leave, you'll be nothing but a bunch of ghost towns and a Disney park.

Signed,
Old People

Dear elderly and their parents:

We've changed the locks on the doors. Don't come back.

~~Other 49 states

Dear other 49 states:

We've changed our wills and when we die you get NOTHING!!! MUAHAHAHAAH!!! Cough...cough!!!

Sincerely,

The elderly

Dear elderly:

Please, please, please don't leave Florida.

Signed,
Sunshine State Armpit-Pant Megastore Emporium

Note: your letter doesn't have to riff off the previous letter, but bonus points if it does.