In A column I have list of URLs looks like

http://forums.digitalpoint.com/thread12475
http://www.bad-domain.com/something987987.html
etc

(its list of bad links already deleted)

Now I have new list of bad links in the same A column, above
Newly found bad link can look almost the same:

http://forums.digitalpoint.com/thread12476
http://bad-domain.com/something987987.html

also new list can can contain absolutely new domains.

How to delete all cells with matched domains (to left only new ones)?