Is there a way to call spinOnce for a specific subscriber?

edit

Inside my node I have several callbacks. I want to avoid using spinOnce() inside my node as much as possible since the current job should always finish what it is doing before the next callback begins. However, there is one instance which I need to wait on a particular message before continuing. The current solution is to run spinOnce() in a loop, but this is not the way it should be done.

Is there a nice way of doing this? I've read a little about creating my own queuing system, but I would like to find a way that requires the fewest amount of changes.