An app to connect Apple watch people to Fitbit people??

I'm sure there is already a thread somewhere for this question but it will probably take less time for me to create a new one than to look for an old one!

So I love the 7 day competition feature that the Apple watch has for other Apple watch users....... but I know a lot of people use Fitbit and I'm trying to connect with other people to keep me motivated. I've tried "Activity.Club" and that app seems to be dysfunctional because I just keep getting an error message when I try to create an account.

Does anyone know how to connect Apple people to Fitbit people??? Thank you in advance!