2 solutions grab me as being correct.
1) Create user groups and permissions in the database using the databases permissions set up... This is of course given that all of the users are "users" in the database. My guess though, is that the script is the only user.

2) Use binary data permissions and groups like in unix. You can have a column for each group if that seems necessary/prudent and binary permissions related to the "file"/executable. Groups could be established in a separate table by over user/group. This also obviously has no problems if a user needs to belong to multiple groups.

Just Another Perl Backpacker