How to setup SSL for Mapped Domains

So I have a WP multi-site install setup on:

We will be selling subsites to churches and of course want to allow them to setup a custom domain. We have all that setup and working.

The rub comes in where I want to plan for the future and allow them to be able to have an SSL certificate setup for each custom domain name.

Our hosting provider (SiteGround) is saying they won’t be able to support this. That each domain name with SSL will require a separate hosting account which obviously won’t work with WPMS.

Do you know of some hosting providers that do support the ability to setup WPMS with SSL enabled sub-sites?