This paper introduces a partner heterogeneity assumption in the one-way flow model of Bala and Goyal (2000, [1]). Our goal consists in the characterization of strict Nash networks with regard to the set of resources obtained by players. We use the notion of condensation network which allows us to divide the population in sets of players who obtain the same resources and we order these sets according to the resources obtained. Accordingly, we can examine the relationship between heterogeneity and asymmetries in networks. We establish that the nature of heterogeneity plays a crucial role on asymmetries observed in equilibrium networks.