Change Mesh/Object Geometry
 

I have a question regarding body motion/modification within a simulation.
I have a problem where I would like to solve a fluid simulation while a object inside changes drasticaly. I also have meshes for each timestep the simulation should be solved. Is there a way that these meshes are used for their specific time steps? If I simply put them inside the according timestep directory they are ignored. I also face the problem that the meshes don't have the same cell count.
I would like to not use the mapFields command every single time step as this would take a lot of extra time.

Thanks in advance for every response to my problem.