Selecting last row (range 1-4)

Selecting last row (range 1-4)

Hi,

No clue if this is really possible. But I have an undefined amount of div-tags
floating in an content div. There are max. 4 divs in a row. Now I want
to select always the last divs to add an extra class. I know to select the
last object but not the last one in a range from 1-4 depending on how
many containers are on the page. Any idea if this is somehow possible?

thx
T.C.