I have new extensions on a kx-td1232-7. I'm going to have to permanently forward it busy/ no answer to their existing kx-tvs125 mailboxes. Is there a way to set it so that it's always on & not subject to the Fwd/Dnd key? I don't want them to hit that key accidently (turning it off)& maybe not lighting the Fwd/Dnd key would be nice......Thanks