def combinationList[T](ls:List[List[List[T]]]) : List[List[List[T]]] = ls match {
 case head :: Nil  => for(x <- head) yield List(x)
 case head :: tail :: Nil =>
  for {
    hl <- head
    tl <- tail
    if tl.forall(te => !hl.contains(te))
  } yield List(hl, tl)
}

case _ => combinationList(combinationList(ls.tail):::List(ls.head))

List ( List(1), List(2), List(3) )

combinationList(List(combinationList(ls.tail)):::List(ls.head))