Conditionals in phrases alternative?

[kpmedia]

I have some pay access sub-forums.
I want to replace the vbphrase "private" with something else.
But not just a single something else, but multiple messages depending on sub-forum.

Phrases cannot use conditionals, leaving template mods.
However, the vbphrase['private'] is not in the templates, but only in the functions_forumlist.php file.
So I'll have to edit the core files (and I'm fine with that).
In the PHP, what sort of conditional statement could be written to allow for multi messages?

Something like this:
if forum = 55 then display vbphrase private_1 on forumhome
if forum = 75 then display vbphrase private_2 on forumhome
if anything else then display default private vbphrase

I've tried a few PHP edits on my own, but nothing has worked so far.

Original:

PHP Code:

else if (!($forumperms & $vbulletin->bf_ugp_forumpermissions['canview']))
{
 $forum['lastpostinfo'] = $vbphrase['private']; 
} 


Failed attempt:

PHP Code:

else if (!($forumperms & $vbulletin->bf_ugp_forumpermissions['canview']))
{
 if ($post[forumid] == 55) 
 { 
 $forum['lastpostinfo'] = $vbphrase['private_1']; 
 } 
else 
 {  
 $forum['lastpostinfo'] = $vbphrase['private']; 
 } 
} 


Help?