Cross-species transmission of pathogens can be facilitated by frequent contact among wildlife. Cross-species transmission is often driven by phylogenetic similarity between host species, but the role this plays when multiple host species co-roost is unknown. We developed a generalizable framework for understanding how cross-species transmission is driven by contact among co-roosting species spanning evolutionary similarities and the net impact on roost-level infection prevalence. We developed ordinary differential equation models describing population and infection dynamics between two and three co-roosting species. We parameterized models using co-roosting Neotropical bat systems, with interspecific transmission exponentially declining with phylogenetic distance. To assess the relative contribution of contact rates and phylogenetic similarity, we co-varied intraspecific transmission rates and phylogenetic distances while considering sensitivity to host and pathogen traits. While our models converged on similar equilibria under high intraspecific transmission or long durations of infection and immunity or latency, simulations with lower intraspecific transmission and shorter such periods revealed roost-level prevalence was greatest when hosts were most closely related. However, we identified regions of parameter space where roost-level prevalence also maximized when hosts were distantly related, driven by species-specific traits. Our generalizable models are adaptable to other co-roosting systems and informs our understanding of pathogen spillover.