Project type custom text field is required

Hi everyone,

I have the requirement in project server 2010.My requirement is that,i have four project type custom text field named as T1,T2,T3,T4. Now when i associate these fields with a PDP (Project Detail Page) i want ,when i entered any value in text box T1 ,then all remaining text box T2,T3,T4 should be Required else text box T1 is empty then all remaining text box T2,T3,T4 should not be required.

Thanks..

Neeraj