search for: second_set

Hi - I have 3 fileds a user can fill out. They can fill out 2 of them or just one of them, for example. fill out these 2 fields: Field1 and Field2 Or fill out this field: Field3 In my model how do I use validates_presence_of for Field1 and Field2 or just Field3. I want to do something like this: validates_presence_of Field1, Field2 OR validates_presence_of Field3 So the user can fill out