Ok, a possible workaround which may be compatible with the future version.
I use gravity forms which allows me to create user profiles. Gravity forms has conditional logic.
So I can have one field dictate the appearance of other fields.
So for example I can have a drop down with the option seller or buyer.
Then I have specific field sets for both which I will be displaying based on what the user selects in the drop down.
That means that you will be ending up with empty fields.
So all that remains is to hide the empty fields (I am sure it can be done with some code if it’s not already there)…