How to additionally filter list of published nodes in Drupal 6

I need to adjust the way which a content is determined as published or not published. The editor of particular content (this is a separate non-administrative role) should have a possibility to set the published flag for particular node (it can be achieved using Override Node Options module directly or by implementing it's techniques). He should also be able to set two additional publication attributes, i.e. publication start date and publication end date (the fields can be added using Content Construction Kit). These optional fields should be used to determine node's published status. Let's say that if specified, they will override published flag.

Basically I would like to be able to add my bits of SQL code to the WHERE 开发者_运维知识库section of proper query or to postprocess result of such query. Maybe to overwrite some function or provide some callback. Solutions based on writing of custom modules are fully acceptable.

I am using Drupal 6.

It sounds like one of either the Node Expire or Scheduler modules should do what you need.