I have a custom workflow. This workflow removes permissions to items when an item is added (example an item is added by a service account and once added those permissions need to be removed from that item). This works as I have the service account 'hard coded' in the custom workflow.

Now I would like to remove this hard coding and when a item is added to a list I would like to iterate through all users that have access to the list item. If a user matches some algorithm then remove that user from the item permissions which will be 0 to many.

The piece I'm stuggling with is how to iterage all users with permission to a SPListItem. Any thoughts on how to accomplish this?

Thanks in advance!