How do I restrict the options in a lookup field to only those dependant on another fields data.
For example, say I had a field for "car make" and another for "car model" . If someone enters "Honda" For the "car make", I want to only be able to choose from a list of Honda models for the "car model" field. Similarly, if they choose "Ford" for car make, I want them to only be able to choose from a list of Ford models. How would I set this up?