The part of the sentence "please join me in welcoming" is correct and usable in written English. You can use this sentence to introduce or to invite your audience to join you in welcoming someone. For example, "Please join me in welcoming our keynote speaker for the evening, Susan Smith."
Please join me in welcoming Marc to JPMorgan Chase.
Please join me in welcoming Larry to UBS.
Please join me in welcoming, Mark Nelson.
Please join me in welcoming George Scangos.
Please join me in welcoming After Eight.
So please join me in welcoming Dominique.
So please join me in welcoming Professor Smith.
So please join me in welcoming Professor Hitoshi Murayama.
Please join me in welcoming Dr. Michael McFaul.
Please join me in warmly welcoming Scott to Time Inc.
Please join me in warmly welcoming Melinda and Bill Gates.
I love the desktop app, it’s always running on my Mac. Ludwig is the best English buddy, it answers my 100 queries per day and stays cool.
Cristina Valenza
Retail Lead Linguist @ Apple Inc.