There is no way to do this via list configuration. You can set a moderator password if there isn't one already, and give the password to these people. If you don't want them to receive regular 'moderation' notices, you don't have to add them to the moderator list.
Once these people have the password, they can approve their own posts or they can pre-approve them by putting an Approved: header or first body line in the post they send to the list.
Of course, they can also approve/reject/discard any other pending moderator requests via the admindb interface.
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Hi Mark,
Ah well nevermind, was just wondering if it was possible. I'll take a look and do some testing with letting (the at the time 2 or 3 members I'd like to be able to do this) moderate themselves, but to be honest it looks like I'll just leave it as is and see how it goes.
Thanks
Dan