Help on Access 2007 autopopulate form fields.

In Access 2007 I want to make a choice (Site) from a list in a field and autopopulate the next field (Owner). The next field should have a list (Technical representative) to choose from based on the first fields choice (Site) and then autopopulate the next field (Tech phone number) based on the choice from the list (Technical representative). The next field should provide a list (QA representative) to choose from based on the first fields choice (Site) and then autopopulate the next field (QA phone number) based on the choice from the list (QA representative).