Dont show "Last Post" for specific thread

[RsX]

I need a hack so that in the forum home, the "last post" (on the right of every forum) wont show only for a specific thread... i need this hack because we have a sticky entitled "the worlds longest thread" which is basically a spam thread... so i would appreciate it if u could make something so that when moderators/super moderators/admins edit a thread (in the thread tools menu) it will have a "Dont show last post" option or something. I hope u understood what i wanted :P

thanks in advance to all who help!