Filter users returned in the 'People' control on a list

Good Afternoon,

I'm in the process of creating a PowerApps form from a SharePoint list and within this list, I have a column for 'Approver'. At the moment, I'm doing a lookup to a different SharePoint list to get a subset of users who can approve.. But.. I lose a lot of the default functionality this way, such as querying the email address from the object.

Would someone be able to point me in the direction to how I could use a People field but filter the possible list of results to a small number of defined users, rather than all of AD?

Many thanks,
Dayna