  We consider two disjoint sets of points. If at least one of the sets can be
embedded into an Euclidean space, then we provide sufficient conditions for the
two sets to be jointly embedded in one Euclidean space. In this joint Euclidean
embedding, the distances between the points are generated by a specific
relation-preserving function. Consequently, the mutual distances between two
points of the same set are specific qualitative transformations of their mutual
distances in their original space; the pairwise distances between the points of
different sets can be constructed from an arbitrary proximity function.
