How passwd_override Handles Multiple Override Entries
When more than one override entry applies to an account, the entry with the most specific account identifier (that is, either a principal UNIX ID, a group UNIX ID, or a principal name) is selected. Principal names are the most specific, followed by the principal UNIX ID and group UNIX ID.
For example, assume that the override file contains the following two entries that override the login shells:
mozart::::::/bin/ksh
:::25:::/bin/csh
If a principal logs in as mozart, the override that is keyed by mozart is in effect. In this case, the principal (mozart) is more specific than the group (25).