Using markers

No, you can't do that at present. You can add individual cue marks during recording, but you have to turn these into ranges afterwards.

Personally I think it's unlikely to be added as a feature. The reason for this is that recording as a process is given the highest priority in your computer, simply so that nothing gets missed. Adding a single cue mark doesn't really amount to a burden, but selecting a range and processing it as such definitely does, and is a significantly greater one. I'm not saying that it isn't possible to do this - just that it would come with risks, especially on slower machines.