Ability to add external users to People column

I need the ability to add a non-Monday user as an assigned Owner to a task in Monday boards. This is strictly for reporting purposes. I need to be able to see how many of each outstanding item across our boards are assigned to specific users - both internal and external. I don’t need (or want) the external user to log in to see or interact with the board. For security purposes, only internal users need to see the board. However, I still need to accurately track who is assigned to what, preferably without having to create a separate Text column for the external users.