What software to send out checks to investors?

I understand this is more of a back office question, but some of you smaller shops may have an answer to this.

We are sending out physical checks to our investors. Our principal is an older guy and all his investors are old too and like to see physical checks. We typically send out checks every month or quarterly depending on the cash situation for each property. Each time we send out a check, we provide a one page letter on our letterhead just giving them a rundown of the updates and it is signed off. Anyone know of any service or third party company we can use that can handle this? If its too much of a headache, we don't mind just getting printing software ourselves to do it.