Yup, to wing up you'll both need to be in the same PG. I assume that you're in the original "Mobius" PG since you joined way back when, in 2015. That group is closed so your wife's account will need to request to join either Mobius Eurasia or Mobius Americas. The instructions on how to do that are here
If you want to have your account in the same PG, you can go through the same 'join' process to request to change PG's. When you get to the screen that asks how you heard about Mobius, select the " I'd like to change my private group" option.
Or, you can create your own PG and wing up there.