Takes two Individual records as parameters and returns TRUE if they are relatives of the 'half blood'. 'Half blood' is the relationship that exists between people who are blood relations of one another, but (if siblings) have only one parent in common or (if cousins etc.) have only one ancestor in common. Note that a cousin who is adopted by one of his parents, but is the birth child of the other parent, would be a full cousin, and not a half-cousin; but he would nevertheless be a 'half blood' relation.
If one person is the direct descendant of another, they are not 'half blood' relations. Also, if two people are related in more than one way, they are only deemed to be 'half blood' relations if their closest blood relationship is a half-blood relationship.
A reference to an Individual record..