Creating dependencies for ticket custom fields - can you?

Hi there fellow thwackers,

We've recently implemented Web Help Desk and after the initial "what do we do with this?", I feel that we've gotten the hang of it and will be going live with it as our Asset and Ticketing system.

However, I have one small question and that is around the ticket custom fields.

1. Service Affecting: Yes; No
2. Services Impacted: Text field
3. Service Impact Start: Date Time

Ideally, of the three fields, 2 and 3 should only be visible/required if option 1 = Yes.

Where as at the moment, the techs needs to answer all three options (all be it with N/A and some random date time) before the ticket can be saved.

Is this possible to create the dependencies?