Ability to Pass Values from one form to a nested form

I would love the ability to pass values from a primary form to nested forms for linked records.

For example, I have a new ‘account’ form and within that form I have a field to link the referral source. I also have another field where users can create opportunities while setting up the account. I would like to pass the referral source to the opportunity(ies) through hidden default values.

A workaround for now will be to watch for new accounts, and ‘continue if’ there are any opportunities, and do a ‘for each’ update of the opportunities with the referral source. Just eats up a lot of workflows.