Resolved! standard NAT acl for n given hosts only
how to change a standard acl from NATing the whole following subnet:ip nat inside source list 1 interface FastEthernet0/0 overloadaccess-list 1 permit 10.120.50.0 0.0.0.255... to some specific hosts on it ... say 10.120.50.1, .3, .5, and .7 only ?ip ...