This tut might help lead you in the right direction:
https://www.nawyecky.com/tuts/tut-baloon.htm
But as for the actual balloon dynamics, that can be achived by adjusting the friction and resilience of each piece of balloon geometry so they bounce off of each other as much or as little as you want
Good luck!
Israel "Izzy" Long
Motion and Title Design for Broadcast-Film-DS
izzylong.com