postcard distribution company

I want to print a bunch of thank you postcards but leave the back blank. I would like to then send these post cards to a distribution house that I can electronically send a mailing list to from my database (weekly/monthly) and have them print the address as well as a special offer on and distribute through the mail. That way I can have them hold generic post cards that I can change the offers as I choose. I understand this can be done with a high speed laser printer. Anyone have any experience with companies that do this.

Thanks for the help.