public boolean isIndirectFamilyMember(@Nonnull Set<InheritanceVertex> family, @Nonnull InheritanceVertex vertex) {
		return this != vertex &&
				family.contains(vertex) &&
				!isChildOf(vertex) &&
				!isParentOf(vertex);
	}
@param family
		Family to check in.
@param vertex
		Supposed vertex that belongs in the family.

@return {@code true} if the vertex is a family member, but is not a child or parent of the current vertex.
recaf-core/src/main/java/software/coley/recaf/services/inheritance/InheritanceVertex.java