Bobby met Jon for the first time in the late 80s (he wasn't too sure exactly when) when he came to a Southside Johnny and the Jukes' show. During the show, Johnny took Jon's leather cowboy hat and threw it into the audience, unbeknownst to Johnny it had been given to Jon by Willie Nelson just two weeks prior. Jon wasn't very happy about that
Later (much later, if they truly met in the late 80's) Jon called him up to come play on his solo record (DA). They lived just 10 mins away from each other.

EDIT: oh yeah and the part about Richie was that Jon and Richie didn't see eye to eye, and tensions grew in the band. They both wanted to take the band to different directions. Not much else.