Can I use all the IPv6 assignment for LAN and one for guest

If I get a /60 IPv6 from ISP and want to assign the first 15 subnets to LAN and the last one to guest, is this possible? Right now there is only option to assign /61 (8) for LAN and /61 (8) for guest, since guest only need one /64 subnet assigning 8 subnets is a waste.