Detailed steps cannot be written from your "for example" instructions.

Generally speaking, you have to create a filter to grab the message from eg craigslist. The filter must create an automated reply and send it (why you would send an auto-reply to a mailing list is a bit scary, but I'll go with it for now). You may need to extract bits from the original message using regular expression macros in the auto-reply template for the filter.

The next step would then be a second filter which grabs the reply when it comes in and auto-replies to that.

Your instructions are too vague and your request too much. Have a read of the TB FAQ sections on macros, templates and filters and try to do this yourself. Then come back here and ask for help with the bits you can't figure out for yourself.

The Bat is more than capable of doing what you wish, but you either have to work it out yourself or hire an expert to save you the effort.