For those who are searching the forum for the same question, this is how i did it:
Make a copy of the "next_image" function, name it "nextUr_image". Put this function into the template "functions.php", add this line on top :
$_zp_parent_album = getUrAlbum($_zp_current_album);
and replaced all "$_zp_current_album" in the function with "$_zp_parent_album". Now you can write your loop on the album.php page like this:
`
while (nextUr_image()):
`
And you will have a query through your Top-Level Parent Album, while you're on a sub-album page.