Easement between attached homes.

[Chootar Laal]

I own two rowhouses and the dividing line between them splits a driveway down the middle in the back.

If I want one of the rowhouses to have access to the full driveway, would I need an easement or a right-of-way? I'm asking because I may sell one of the rowhouses in the future.

Also do I need an attorney to do the easement for me or I can write one up myself? Anyone in the Boston area who can help?