We offer individual and joint membership with a couple of different rates for each type. I have created a price set that has 2 price fields and each price field has a couple of options. I want to set the price set so that only one option can be ticked across both price fields. There isn't an option for this and but I hope someone has a solution. I can put all types of membership into 1 price field but it reduces the system options and makes laying out the contribution page harder. Any help appreciated.
Yes, the price fields are independent, and the design limits you to putting all the membership types/flavours into one price field if you need to force only one.
A simple alternative is to create separate contribution/membership pages for each membership type - so the visitor would be presented with different links for each membership type before getting a form. That allows your form to be simpler and have additional membership-type-specific messaging and behaviour.