Ask HN: Browser Extension for Multiple “Contexts”?

I usually have a few instances of my browser open (firefox) and try to keep each instance with a related group of tabs. In other words, I'll keep all "research" links open in one instance and work-related links in another. Is there any extension that would allow me to: a) "Name" running instances and separate them into different task bar buttons as opposed to group everything into one? b) Save such instances as "presets" so I can quickly launch them?