[TYPO3] Setting a shortcut dynamicly

[PEF]

Hi

In my menu I have a shortcut that points to a subpage. On certain 
conditions I want to points this shortcut to another subpage. The reason 
for this is, that when conditions are met, the first page will be 
hidden. In state one both pages are visible.

I've tried to change the shortcut through php, by setting the shortcut 
parameter for this item in $menuArr. But without luck.

Is it possible to change a shortcut dynamicaly? Or is there another way 
of doing this, that I haven't been aware of?

Shortcut
--- condition 1
--- condition 2

Just in case.... I know that the problem would be solved by setting the 
shortcut to the second page from the beginning. And this could of course 
be the final solution.

Bye
Peter