Map transformation - combine two maps

groupMaps.scala

def groupMaps[A,B,C](m:(A,Map[B,C]))(n:(A,Map[B,C])):Map[B,Map[A,C]] = {
  (m,n) match {
    case ((a,mm),(b,nn)) if mm.nonEmpty && nn.nonEmpty =>
      Map(mm.head._1 -> Map(a -> mm.head._2, b -> nn.head._2)) ++ groupMaps((a, mm.tail))((b, nn.tail))
    case ((a,_),(b,_)) => Map.empty[B,Map[A,C]]
  }
}

val hostA = ("hostA", Map("/oauth2/token" -> "1", "/carts/default" -> "2"))
val hostB = ("hostB", Map("/oauth2/token" -> "3", "/carts/default" -> "4"))


val host1 = ("hostA", Map("/oauth2/token" -> 1, "/carts/default" -> 2))
val host2 = ("hostB", Map("/oauth2/token" -> 3, "/carts/default" -> 4))

groupMaps(hostA)(hostB)

groupMaps(host1)(host2)