Is it possible to source pricing groups in a custom field?

Yes, but need to use suitescript

Can you explain how ?

Create a client script and on field sourcing or field change or validate field (based on your requirements use any one method) search the price group and store it in custom field

I wanted the ability to have that data on the server side as well. I guess I will have to create a custom list which matches the pricing group.

For server side you can create a user event script and on before or after submit search the price group and store it in a custom field. If you need more information kindly DM me.

I got it. It's just not something I was hoping for, thank you.