Direct Mail Providers With Do It Yourself Drip Campaigns?

[David Ounanian]

Who is everyone using for direct mail?  I want the ability to setup a drip campaign online and then be able to add addresses in bulk or one at a time as I come across them.  Does anyone have any recommendations for online direct mail providers that can do this?

Example:

I setup a drip campaign to mail a postcard every 2 weeks for 4 months.

I import a list of 100 addresses to my campaign and the mailers start going out.

A week later I add 20 more addresses and those mailers start going out.

2 weeks later a friend tells me about a house and add 1 more address and mailers start going out to that house.

Etc