In what way does it limit you to three? Add an addressee, click return and it opens a new address box for the next one. Look for the scroll bar which allows you to cycle through the addresses.

If you use the visual Contacts Sidebar, just keep using "add to..." and it will do this for you.

If you grab the horizontal separator line just above the message text area with the mouse, you can drag it downwards, increasing the amount of space for displaying addresses, and hence see more than the default three lines.

Well duhhh. I limited myself to the 3 places that I could see and always gotten out of there by a mouse click, but never tried hitting the return key on the 3rd place.

I appreciate your help