Fans of the long-running music-and-dance phenomenon Soul Train will want to be in attendance for this weekend's Martin Luther King Jr. Holiday Concert Celebration. Regina Belle had her biggest hits singing duets, first with the Manhattans and Johnny Mathis and then, in 1992, with Peabo Bryson for "A Whole New World," the theme to Disney's Aladdin. As a founding member of Shalamar, Howard Hewett made some sparkly uptown R&B singles before going solo and scoring a few top-ten hits. With songs like "Kissing You," Keith Washington favors a more slick style of slow jam. Taken together, this trio promises to provide a serious '80s soul flashback.