You can add to your nsswitch.conf file compatibility with the +/- syntax sometimes used in /etc/passwd, /etc/shadow, and /etc/group files.
NIS+. To provide +/- semantics with NIS+, change the passwd and groups sources to compat and add a passwd_compat: nisplus entry to the nsswitch.conf file after the passwd or group entry as shown below:
passwd: compat passwd_compat: nisplus group: compat group_compat: nisplus
passwd: compat group: compat
This specifies that /etc files and NIS maps as indicated by the +/- entries in the files.
Users working on a client machine being served by an NIS+ server running in NIS compatibility mode cannot run ypcat on the netgroup table. Doing so will give you results as if the table were empty even if it has entries.
See the switch file chapter of Solaris Naming Setup and Configuration Guide for step by step instructions on adding +/- semantics to an nsswitch.conf file.