How to restrict the People Picker Control (on Mobile Apps) to a specific SharePoint Group

We are using Classic. I should mention that our version of forms is a wee bit (a lot) out of date 2.9.0.0 (I'm looking to do an upgrade soon)

Interesting. An unconnected PeoplePicker control has the filter.

When I connect it to the Person field in my list, the option goes away.

Thank you Sean,

Now how do I place the value of the unconnected control into the connected one if I can't use javascript in the mobile app?

Further Update

I've gone and tried creating a column directly from the Nintex Form designer with the correct filtering right from the start, and the filtering works.

So my issue is only that Nintex Mobile form doesn't correctly pick up the settings if they are not setup initially that way. (or it could be SharePoint just doesn't update the property correctly?)

Final Update (Found the solution)

Ok, so it's actually a really simple solution. Nintex form does not update the settings when they're changed if the control is already on the form. When changing the filtering, it seems necessary to remove the control off the form and then re-add it again. This then correctly works in the mobile app when published. Thank you Sean for setting me on the right path.