You may have to train each one separately, at least at first. (I see the beagle's point, poor boy, a click and no treat!) If the click isn't eliciting a response, try loading the clicker again. (Loading is clicking, then immediately giving a treat until the dog looks to you for a treat as soon as they hear the sound.) Load it with a higher value treat this time, like cooked chicken, hot dogs, cheese, whatever really interests the whippetx.
They do sell a double clicker which makes two separate clicks, maybe that would help. You would have to train the whippetx to one and the beagle to the other.
It's not uncommon for #3 to happen. When I trained Muggsy to stop barking on command, at first I was lucky to get half a second of silence. What I did was to lengthen the time between the command and the reward. So at first I'd give the command and immediately treat as soon as he stopped, but then I would wait 2 seconds, then 5, then 10, etc. Eventually, I could reliably get 5 minutes of quiet, even in the face of continuing provocation. (People walking by are so provoking!)
They do sell a double clicker which makes two separate clicks, maybe that would help. You would have to train the whippetx to one and the beagle to the other.
It's not uncommon for #3 to happen. When I trained Muggsy to stop barking on command, at first I was lucky to get half a second of silence. What I did was to lengthen the time between the command and the reward. So at first I'd give the command and immediately treat as soon as he stopped, but then I would wait 2 seconds, then 5, then 10, etc. Eventually, I could reliably get 5 minutes of quiet, even in the face of continuing provocation. (People walking by are so provoking!)