Metadata Validation

System

Hi

I am trying to put some Validations in metadata Capture form, But am not able to do so. Is there any workaround possible for this? My requirement is something like this :
Depending on the option selected from a select list of one field i need to make another field as read only.

I am using TS 5.5 on SunOS 5.8


Ideas?
Suggestions?

Thanks