Existing research has shown that in wind farms, if the dynamic characteristics of wind turbines of the same type are similar, the increase in the number of wind turbines will lead to a "collective impact" among the turbine groups, posing oscillation risks to the grid-connected wind farm and potentially causing oscillation instability in severe cases. In practice, a wind farm may consist of different types of wind turbines, such as direct-drive and doubly-fed wind turbines. It raises the question of whether similar dynamic characteristics among different types of wind turbines in hybrid wind farm might also provoke a "collective impact". The paper first establishes a linearized model of the hybrid wind farm connected to the external power system. And then, it reports the finding of the "collective impact" among different types of wind turbine in the hybrid wind farm and demonstrates the influence of the change in the number of grid-connected wind turbines, the difference in dynamic link characteristics among wind turbines, and the line reactance on the "collective impact." The correctness of the analysis is verified through time-domain simulations. The results of the research suggest that in hybrid wind farm consisting of different types of wind turbines, if similar dynamic characteristics exist among these different types, they can indeed produce a "collective impact". With an increasing number of these different types of wind turbines, oscillatory instability can occur in the hybrid wind farm.