Boss 1 and 2 in CT take what? 15 minutes to complete? Tanks, which seem to be the only role that complains about the JiP feature get instant queues most of the time. So, to get to the point you want to be, it will take you 15 to 20 minutes. DPS have to wait for the queue to pop for 30+ minutes before starting at the beginning.

Seriously, just do the whole dungeon and stop complaining. If you're ok with an in progress group, tick it off and click to join. Declining 50 times in a row because you only want the last boss is annoying for everyone else trying to start a new group. If the DPS can wait for 30+ minutes for a pop, then you can spend 15-20 clearing the first 2 or 3 bosses.