meta command to skip

I would like to create a command that will skip to a later trial if at any point a subject presses a certain key, such as "end" (can by anything). I basically need a way to end the session early at any point. Is there a way to easily do this with meta-command? I have hundreds of trials, so I'd prefer not to have to go through and add a skip command to all of them.
Thanks.

You (or they) can press Escape at any point. That will end the session and write the data accumlated to that point. Will that help?