In the late 1990's, bandleader Leitheiser and his group, The Boomers, opened the show for legendary pop singer B.J. Thomas("Raindrops Keep Falling On My Head", "Hooked On A Feeling") at the Prairie Capital Convention Center in Springfield, Illinois.

As members of The Boomers, bandleader/bassist Kevin Leitheiser, drummer Bob Young, and guitarist Bob Hagler opened the show for the Shirelles at the Decatur, Illinois Celebration, and then provided the accompaniment for the Rock and Roll Hall Of Famers' hits "Soldier Boy", "Will You Still Love Me Tomorrow", "Baby It's You", "Mama Said", and "Dedicated To The One I Love". A year later, the group provided the same service again for The Shirelles and The Crystals("Da Doo Ron Ron", "He's a Rebel", "Then He Kissed Me")at Springfield and Decatur, Illinois venues.

Bandleader/bassist Kevin Leitheiser, guitarist Bob Hagler, and other members of the Rusty Halo Band opened the show and then provided the accompaniment for The Paul Robi Platters' hits("Only You", "Smoke Gets In Your Eyes", "Twilight Time", "Great Pretender", "Harbor Lights", "My Prayer") at the Springfield, Illinois Hilton.

As leader of the Rusty Halo Band, bassist Kevin Leitheiser opened a series of shows for Chicago's Chi-Lites("Have You Seen Her", "Oh Girl") in Springfield, Bloomington, and Decatur, Illinois.