Help with new mod preg_replace

[ericgtr]

I have created custom bbcode that uses a tag for this mod https://vborg.vbsupport.ru/showthread.php?t=72162 , what I want to do is secure it so only registered users can view it and unregistered users see a "Must Register" notice. I am having trouble with the preg_replace function. Here is my idea of what to add to functions_bbcodeparse.php

// Media hack begin
<if condition="$post[usergroupid] == 1">
$string= "song";
$pattern= "#\[mp3\](.*)\[/mp3\]#esiU";
$replace= "<b>You must be registered to view this</b>";
echo preg_replace($pattern, $replace, $string);
</if>
// Media hack end

I know this is off, especially the $replace but hopefully this will give you an idea of what I am after, any help would be appreciated.

[filburt1]

I have created custom bbcode that uses a tag for this mod https://vborg.vbsupport.ru/showthread.php?t=72162 , what I want to do is secure it so only registered users can view it and unregistered users see a "Must Register" notice. I am having trouble with the preg_replace function. Here is my idea of what to add to functions_bbcodeparse.php

// Media hack begin
<if condition="$post[usergroupid] == 1">
$string= "song";
$pattern= "#\[mp3\](.*)\[/mp3\]#esiU";
$replace= "<b>You must be registered to view this</b>";
echo preg_replace($pattern, $replace, $string);
</if>
// Media hack end

I know this is off, especially the $replace but hopefully this will give you an idea of what I am after, any help would be appreciated.
echo preg_replace("/\[mp3\](.*)\[\/mp3\]/esiU", $replace, $string);

[ericgtr]

echo preg_replace("/\[mp3\](.*)\[\/mp3\]/esiU", $replace, $string);
Thanks filburt1, I am still having trouble though. I have tried several variations of this and can't seem to get it right. I tried adding the line you gave me to the bottom, like this:

// Media hack begin
if (is_member_of($bbuserinfo, 6))
$string= "\[MP3\]song\[/MP3\]";
$pattern= "#\[mp3\](.*)\[/mp3\]#siU";
$replace= "<b>$1</b>";
echo preg_replace("/\[mp3\](.*)\[\/mp3\]/siU", $replace, $string);
// Media hack end

Both with and without the e (execute) function.

I also wonder if I shouldn't be applying this to showthread.php instead of functions_bbcodeparse.php? So you guys know exactly what I am after here I created a new bbcode www.site.com/song.mp3 and I don't want that bbcode to show up for a specific (unregistered) group. Thanks again for any help :)

[ericgtr]

I thought I would bump this, I have spent hours trying to come up with a solution with no luck.