Change to "Can View Thread Content" permission

[Wuushu]

Hello everyone, I recently purchased vBulletin and so far I'm amazed with the system of how templates and editing works. I came from phpBB, and have to say I don't miss the constant uploading thru FTP and use of Dreamweaver to change templates!

Now to inquiery,

The permission "Can View Thread Content" stops/allows people to enter a thread (and view post + replies within.)

How would I change it so that this permission is instead working to stop/allow people to view the first post within said thread, only.

That is, if the permission "Can View Thread Content" is disallowed, the user would be able to enter the thread, and see "Can't read first post" instead of the first-post message, but still view all replies.

And if the permission "Can View Thread Content" is allowed, he would be able to enter the thread normally.

Hopefully anyone with a bit more knowledge on the subject can help me, I've been looking thru the template files but it's all still a bit new to me.

Sincere Regards,
Christian