Is there any way to moderate thread but not reply?

[hymoo]

Hi, to battle spams, this is what I want to do:

usergroup A can make new thread in subforum X instantly

but usergroup B, when they want to make new thread in subforum X, the threads will be moderated. However, usergroup B can post new replies instantly, just when they want to make new thread in specific subforum.

How to do these?

*PS: I know I can set up "follow forum moderation rules" but it will also moderate all of their new posts (I only want to moderate their new threads, not new replies)