I could be wrong as there may have been some changes, but it is (was) not possible to set up a key for "system" owned calls such as queues. I believe there are some changes coming in V15 that may help some, but I do not know if it addresses your specific thought. You may want to review the log for V15 changes as well as the idea forum to see if similar requests have been submitted and what, if any, support they received.
I guess the questions are: how will one know that there is a call in the Q (to use a Q call pick up feature) and how will the key be expected to reflect a given status (if at all)? If they will know by virtue of hearing an agent's phone ringing, then the question is why isn't the agent answering or, if not there, why still logged in?