Probably not feasible in a clean fashion with a standard conversation, thanks to anyone for correcting me if I'm wrong.
ZDialog would allow you to do this and much more, however, but that's a rather advanced subject. The system itself, once trimmed(thanks to the improvements made by friends Henesua and Lightfoot8), contains 19 scripts, but once installed, it allows you to build as many convos as you wish, each one using a single script, whatever the number of checks or "actions taken". For instance, in my PW, all merchants, smiths, enchanters etc. use the same single convo, yet they offer different services and tell you different things, and I don't need to know in advance how many available PC replies will be displayed, which is the main strength of dynamic dialogs.
If you're building a few small convos and don't need such flexibility, you're better to stick to the standard system, as you'll end up with about the same number of scripts and the convos will be simpler to build. On the other hand, if you plan to build several medium/large convos, ZDialog will reduce the required number of scripts and you'll also gain a lot of flexibility in the process(personally I don't use a single standard convo in my mod).
Kato