Band will play single during ongoing joint trek with Hall and Oates
Train singer Pat Monahan accompanies on track previewing bands' co-headlining summer tour
Groups will each play individual sets and collaborate at end of each night for joint performance
Country crooner duets with Train frontman Pat Monahan
Singer cancels show in solidarity with Change.org petition
Band was set to perform at National Scout Jamboree in July
Pitbull, Paul McCartney, Cee Lo Green and more gather in New Orleans
Three acts advance to finals, Train gets pitchy on 'Drive By'
Musicians hype party app during Google I/O conference
Plus: Iffy 'American Idol' timing, hip-hop's weak point
San Francisco band performs 'Drive-By,' 'Drops of Jupiter'
"It's a powerful little instrument," says Vedder. "I've got so much respect for it."