A technique is presented to combine data points, each available with point-dependent uncertainty, when only a subset of these points come from ¡ £ ¢ sources, where ¡ is unknown. We detect the significant modes of the underlying multivariate probability distribution using a generalization of the nonparametric mean shift procedure. The number of detected modes automatically defines ¡ , while the appurtenance of a point to the basin of attraction of a mode provides the fusion rule.