Crowd simulation (2)

in the new features tour there's a video on crowd simulation. Can you elaborate more on this feature? Is it integrated in XSI Advanced or is an additional plug in like cloth ?

I think that's refering to to the character substitution workflow found in Netview > XSI Local > Tools > Animate > Character Substition.
If you open it up and press the help button it gives details on how it works.