CloudPanel greatly reduces complexity of running your own Microsoft Exchange environment for multi-tenacy. It features a complete web interface that you can customize/brand and even lock down certain permissions so you can assign certain tasks to other employees while not having to grant them full access.
Download CloudPanel for FREE
The best thing is you can download and try CloudPanel today for FREE! CloudPanel includes up to 250 users in the free edition and more user licenses can be purchased in block amounts on a yearly basis!