Mark Spam As Read

Thank you Zoho people for making such great products. Anyway, I currently use Zoho Mail over IMAP on various devices. I recently switched the Zoho spam filter back on after using client-side filters for a while. I've come to realize that the spam folder shows up in IMAP as containing a lot of unread messages. I want to be able to access spam over IMAP, but I would also like them not to display as unread. So I tried to set up a filter to mark all spam messages as read, but I didn't see a way to trigger the filter on being spam. Is there a way I can automatically mark all spam as read? Thanks.