postbit conditional for advertisements - need help

[karlm]

I'm currently using the below code to place an advertisement within the 3rd post and only to guests.

PHP Code:

<if condition="(is_member_of($bbuserinfo,1)) and (($post[postcount] % $vboptions[maxposts] == 3))"> 


I would like to have it so I can multiple advertisements depending on the post. I already have the random ad code sorted, but what is confusing me is how to get the different posts in the same line.

For example, I had used:

PHP Code:

<if condition="(is_member_of($bbuserinfo,1)) and (($post[postcount] % $vboptions[maxposts] == 3)) or (($post[postcount] % $vboptions[maxposts] == 6)) or (($post[postcount] % $vboptions[maxposts] == 9))"> 


However, when I use this, it shows advertisements to all usergroups (as if it is ignoring the first conditional).

I had assumed I would use the OR statement, but I'm guessing that's not the case. Anyone got any ideas, please?

Cheers.