Configure People Picker to search in all OUs except one

Hi there

I've been looking at PeoplePicker - setsiteaccountdirectorypath - and I know that only a single OU can be set at a time when the setsiteuseraccountdirectorypath operation is used. As a result, this operation should only be run once per site collection

Is there any way that PeoplePicker can be configured to search all OUs except one? Or even to search in more than one OU?

Thanks

Jonj