Hi Fitmum33.
I think I can help but I believe you might be disappointed in my answer.
I've had a similar but slightly different problem in that I wanted to connect multiple devices (but in my case, different ones) to my app to swap between them during the day/week. I have troubleshooted the problem for several days only to finally get a hold of somebody at the Fitbit service dept who knew what they were talking about and they sent me this link:
https://help.fitbit.com/articles/en_US/Help_article/1715/?q=multiple&l=en_US&fs=Search&pn=1
Apparently you cannot connect more than 1 device to your account if it is a "Fitbit Charge 3, Fitbit Ionic, Fitbit Inspire series, and Fitbit Versa series, only connect one of these devices to your account at a time". In my case it was resulting in my steps being erased. I had also connected a Charge 2 and Flex 2 which worked harmoniously together for the last 2.5 years...… until now. Annoying to say the least.
My daughter has a Fitbit too, so we created a kids account under the "My Family" section - I'm sure I could add the second device of the same as mine, in this case an Inspire HR under the kids account separate to my own parent account but within the same app?
But good luck and hope this helps.
