As stated, salaries don't match. The only way you could go all in, have salaries match, and have a remote chance of convincing both teams to give up these two all-stars would be:
http://basketball.realgm.com/tradechecker/saved_trade/6878104Pacers get Bradley, Zeller, Rozier, and 2017 BKN #1
Bulls get Crowder, Brown, Smart, Jackson, and 2018 BKN #1
Celtics get Butler and George, and still have salary cap space to pick up another top tier FA.
Basically, you mortgage your future for a 3-5 year window that doesn't include any depth off the bench. However, your starting 5 is stacked. Pacers and Bulls would both have to decide that they are unwilling to contend for at least the next 5 years in the east, and that they are taking a slow road of youth development.
It's fun to dream, but getting both teams to help you build the next superteam in the east is next to impossible.