Wow. Ladysmith Black Mambazo, the venerable South African male a cappella group who netted international appeal thanks to Paul Simon’s Graceland, sure have a lot of friends. Many of them are familiar American names, like Dolly Parton (“Knocking on Heaven’s Door”), Emmylou Harris (“Amazing Grace”) and Melissa Etheridge (“Diamonds on the Soles of Her Shoes”), whose female pipes contrast nicely with Ladysmith’s unceasingly impressive vocal resonance. And Lou Rawls (“Chain Gang”) and Chicago’s Bill Champlin (“River of Dreams”) work the nostalgia angle with some success. However, several of Ladysmith’s other friends are just plain schmaltzy: Josh Groban (“Weeping”), Andreas Wollenweider (“Passage to Promise”), and Michael Ball (“Bread of Heaven”) collectively suggest that it’s possible to actually have too many. Simon pops up a couple of times, too (“Homeless,” “Diamonds”), of course, but he’s probably more relation than pal by now. Ladysmith has other amigos closer to home, fortunately, and “Shosholoza” (with trumpeter Hugh Masekela), “One Blood” (Mbongeni Ngema), and “Angimboni Ofana Naye” (SABC Choir) provide three of this expansive set’s deeper and more intimately South African moments.