I would like to know whether we can configure more than one crypto maps on a single interface?
You cannot use more than one crypto map on an interface but you can use separate entries within the same crypto map ie.
crypto map vpn-set 1 ipsec-iskamp
crypto map vpn-set 1 set peer x.x.x.12
Your next VPN would be
crypto map vpn-set 2 ipsec-isakmp
crypto map vpn-set set peer y.y.y.15