The phrase 'please join me in wishing' is correct and usable in written English. You can use it when expressing the desire to have someone join you in expressing good wishes for something. For example: "Please join me in wishing my brother a happy birthday!".
Please join me in wishing her all the best.
Please join me in wishing Christian, Paul and Michael success in their new roles.
Please join me in wishing Shyam, Taylor, Kevin, Leo and Claus well in their expanded roles.
Please join me in wishing Jonathan every success for the future".
Dear Sailors, Please join me in extending best wishes to Nick Nash, our Group President, who will be retiring from our company at the end of 2018.
Please join me in congratulating Sam and wishing him every success in his new role.
Please join me in congratulating Scott and wishing him and the entire M&A management team continued success.
Thanks to Ludwig my first paper got accepted! The editor wrote me that my manuscript was well-written
Listya Utami K.
PhD Student in Biology, Bandung Institute of Technology, Indonesia