More than one "organization" for Email marketing?

Susan Bernier

I work for Covenant Health, which operates 3 hospitals and 10 post-acute facilities. We have a single RE account, where we manage donors and online giving pages for each facility. The way that email marketing is set up, I can only email "from" one organization. Has anyone figured out how to use email marketing for more than one organization's address, email, etc.? Or am I stuck in Constant Contact?