Are there any platform that allows mass direct mail campaign?

I can't find anything online that seems to fit my needs:

1. Submit a csv with (First, Last, Address, other fields)
2. Print letters with the information formatted in the right fields
3. They do the printing/ mailing for me.

Only ones I have seen that "seem" to do this is thanks.io and mail joy. However, they only allow 1 page letter which is not sufficient for my needs.

Has anyone run a direct (snail) mail campaign? What did you use to process all those mails?