Complex sentence: The DeMarco Sisters were originally a vocal trio (consisting of Anne, Gina, and Gloria) which was discovered by Paul Whiteman who featured the group on a June 28,1936 broadcast of "Paul Whiteman's Musical Varieties".
Split into simpler sentences: The DeMarco Sisters were originally a vocal trio consisting of Anne, Gina, and Gloria. The girls successfully drew the attention of Paul Whiteman who featured the group on a June 28,1936 broadcast of "Paul Whiteman's Musical Varieties".