@travelin cat, yes, using the right forum helps :) very professional of me, I know! Next time I'll check the whole list of forums.
@lexpixel, it would take me ages because I'm talking about content in bulk, but actually, your idea showed me the right way. There is a plugin called Auto-Schedule Posts by Mr David Miller - it catches any flow of content that comes towards a site and force-schedules posts according to your instructions. It will handle any number of posts. Problem solved! Thanks!