[Typo3] BE: How to make fields mandatory

[Robert Markula]

I want certain backend fields from certain content element records to be 
mandatory for certain users. :)
E.g. The members of the usergroup news_editors should not be able to 
save a news record unless they fill out the fields I set to 'mandatory' 
- Title, Subtitle, Keywords, etc.
I think I have read about this somewhere in the documentation, but I 
can't find it anymore.
Does anybody know where to find this information?

Regards,
Ro