I have, on a contract object, two fields. One is a service frequency, and one is billing. They are very similar, except I want to make a dependency so that if the service frequency is quarterly, let's say, the billing frequency cannot be monthly or weekly. Essentially, I want it to be at most as frequent as the services.
I want the controlling field to be service frequency, but when I select it, I cannot choose billing frequency as an option. Any idea why?