The Pointer Sisters
The group had its origins when sisters June and Bonnie Pointer began performing in clubs in 1969 as 'Pointers , a Pair' . 
<triplet> June <subj> Bonnie Pointer <obj> sibling <subj> 1969 <obj> work period (start) <triplet> Bonnie Pointer <subj> June <obj> sibling <subj> 1969 <obj> work period (start)