Azure - Killing a particular roleinstance

Hi,

I've got a situation that I need to kill a specific roleinstance running in cloud through the management API.

more specific, I have 3 rolsinstances under a deployment (inst1, inst2, inst3 where inst3 is the youngest) and need to kill instances when they go into idle status which means it is done with its task, and no more tasks in the queue.

Is there a way to kill particular instance rather than changing "Instance count" value in service configuration file?

Thanks in advance

Dan