to have the removing site on the listing site completely remove

Hi, I have this code in my css:
#post-286 > div > div > table > tbody > tr:nth-child(3) {
display: none;
}

The purpose of this code is to remove one of my site called "beauty eBooking" from "salon listings" menu tab, because this site will reserve to display information about my main site which is link to one of my tab menu called "add a business". So now, I have a problem:

Every time I added a new site, this removal site "beauty ebooking" popped back to my 'salon listings" How can I permanently remove/hid this site from the "salon listings" tab so it will not reappear on the "salong listings" every time I add in new site?

Thanks
chad