There's no way to transfer a board that I know of, but you can create a group board and invite people. You can also join other people's group boards.
You can find group boards and also find people who are interested in any topic by doing a search for the topic in the Search box at the top of Pinterest. Once you've done your search, choose the "Boards" link. This will show a variety of boards that already exist for that topic. Choose "Pinners" if you want to see like-minded individuals you can follow.
You can then invite people to a group board you've created or you can further search the boards that showed up when "Boards" was clicked to look for group boards that already exist. You can recognize a group board because it has a little symbol next to the board name that looks like three people in a cluster..
To create a group board of your own, click "Edit Board" on any board. You can then enter a person's Pinterest name (found in large letters at the top of their Pinterest page) in the "Who can pin?" field and click "Invite." Pinterest will automatically send them an invitation. Be aware that you have to follow someone before you can add them to a group board.
Any group board you belong to -- whether you created it or someone else did -- will show up on your Pinterest page.