Bivariate survival models with discretely distributed frailty based on the major gene concept and applied to the data on related individuals such as twins and sibs can be used to estimate the underlying hazard, the relative risk and the frequency of the longevity allele. To determine the position of the longevity gene, additional genetic markers data are needed. If the action of the longevity allele does not depend on its position in the genome, these two problems can be solved separately using a two-step procedure. We proposed an extension of this method allowing us to search the position of two longevity genes at a chromosome using the bivariate survival data with correlated competing risks combined with genetic markers data. We have studied the properties of the model with two longevity genes located on the same and on different chromosomes using simulated data sets.