I have 2 garage doors that use Liftmaster remotes. I was trying to program the door openers in one of my cars. Problem being I had 2 remotes that worked the same garage door. I need one of them to work one door and the other to work the other door. That way I can use the remotes to program the remotes in my car. I took one of the remotes and followed the instructions as best as I could. I pressed the green button in the transmitter, light comes on, held the remote button down, light in transmitter flashes and turns off. I figure I'm done. Well, now that remote works both doors. Both go up and both go down with one push. Do I need to erase the remote somehow? I took out the battery and pressed the "on" button a bunch of times. Went back to program at the transmitter again but the doggone remote still opens both doors simultaneously. The doors are 1994 editions and I can't find the owner's info.