Is it possible to disable Safari extensions when using Private browsing?

I recently switched from Chrome to Safari for a few choice web applications, and I found that I couldn't disable extensions like Lastpass when browsing privately, at least not apparently, like I could in Chrome (which disables extensions by default in Incognito).

Is there any way to do this from the Safari UI? I have an Applescript snippet I'm using to disable extensions, and toggle them back on when I'm done, but it's sort of a hassle, and I'd like to make this a default for Private browsing.