I am using virtualbox to test software on various linux distributions. The base Application (10-20GB CAE Suite) is stored on separate vdi, so I can have one vdi per Version of the Application and attach them to multiple virtual machines. These vdi are dynamically allocated and multiattach. Now I want to make a change, so that different versions of the CAE Suite use no extra space for identical data. Let's say I have V1 on v1.vdi and V2 on v2.vdi. They're similar enough, that say 50% of the data is the same. v2.vdi would refer to v1.vdi in the same or similar way as the drives on the various machines refer to the same base image using the multiattach feature.
I think there is some differential storage, which I want to employ. I cannot find the settings in the virtual media manager, that allow me to do this. I am willing to do this on the command line, but couldn't find it either. Host System is Windows.