_{(answer to question by bernd_k)}

For sharing files between the host and guests, one actually shares directories rather than files.

If the network mode is bridged, then the host and guests are each equal network partners. Although the whole setup is contained in the one host, network-wise they are all equal on the network, as if they were physical machines.

This way, any shared folder in any computer, virtual or physical, is available to all. Because not all virtual machines may be turned on all the time, it makes sense to setup one folder of the host as the shared folder. The host then shares the folder, and the virtual machines use it as-is or as a mapped drive.

The following article explains with great detail how to share folders in Windows :
How do I share folders in Windows 7 with the Shared Folder Wizard?

_{(answer to question by bernd_k)}

For sharing files between the host and guests, one actually shares directories rather than files.

If the network mode is bridged or NAT, then the host and guests are each equal network partners. Although the whole setup is contained in the one host, network-wise they are all equal on the network, as if they were physical machines. (NAT is sometimes more problematic to use than bridged.)

This way, any shared folder in any computer, virtual or physical, is available to all. Because not all virtual machines may be turned on all the time, it makes sense to setup one folder of the host as the shared folder. The host then shares the folder, and the virtual machines use it as-is or as a mapped drive.

The following article explains with great detail how to share folders in Windows :
How do I share folders in Windows 7 with the Shared Folder Wizard?