jQuery UI autoComplete - 从另一个字段传递一个值

I'm attaching jQuery UI autocomplete to a contact field which works, but now I need to also pass a company_id (dynamcially) to restrict the search not only to the search characters but also to a company that the user has previously chosen. IE if the user enter 'jo' all contacts that contain 'jo' that are within the company_id passed.I'm attaching jQuery UI autocomplete to a conta