Need Help! Autodesk Inventor to SolidWorks

I have an entire assembly made of very many parts in Inventor and I want to convert it to a SolidWorks assembly. I have both programs installed on my computer, but every time I open the Inventor assembly file in SolidWorks none of the mates go through. Mating everything again would take forever. Is there any way to make it stay together when transferred?

Thanks!