I have created a custom validation function in my model. I know each rule (and subsequently my validation function) can return one error message as is defined in the $validation array. But my function checks multiple conditions and I would like to return a more tailored and conditional model validation error message instead of a more generic one. For example, instead of displaying "You haven't passed condition A or B" as the rule message, I would like it to say "You haven passed condition A", "You haven passed condition B" or "You haven't passed condition A and B" depending on which one was breached. Is that possible? If so, how do I do that?