Currently I have a Membership Options price set on my registration form. It is a radio button widget, showing the available options.
In this paradigm, the currently logged in user who is already a Member has to do something like choose an option "I am already a Member" to see the correct price set options. This relies on a trust model.
How can I show or hide a price set based on if someone is a logged in member?
EDIT: The reason I did not use CiviDiscount is that AFAIK discounts can't be 'stacked' so if I auto apply a discount to price set options based on Membership, then a user can not enter an additional discount code and have them both work.