Transfer: Easement Use by Adjoining Neighbor

My question involves real estate located in the State of: California

My home and vineyard is accessed via a road that goes over my neighbor's property. I hold an easement which allows me to access my home, and to have vineyard equipment come in as well.
There have been no problems with this easement of any kind.

I now wish to 'sell' a part of my vineyard to another person (via a lot line adjustment), which is allowed by the county.
Although this section abuts his land, he would prefer to use my roadway to get to this section of the vineyard.

Can my buyer access his section of the vineyard through my existing easement, or does he need to get a second easement from the owner of the property he would pass over?

Thanks.

Transfer: Easement Use by Adjoining Neighbor