conditional in bbcode - display bbcode only for guest

[bartek24m]

Hello i have been add new custom bbcode which all my users used in their threads and i would like to divide this one bbcode for condition member & guest

like
[zs]
Hello member {param}

Hello guest {param}

[/zs]

and bbcode show only for guest or members code

i try to add up condition

<if condition="$show['member']"></if>
AND
<if condition="$show['guest']"></if>

there is some hack to do sth like that ?