There is a section in the user's guide about writing data to a common networked location so that all the data can be gathered in one place. Currently, it's a global preference so it would affect everybody if you do this in the default preferences file. However, you also have the option of creating additional preference files. Doing so, you could allow the network data option for some and allow the default local option for others. Personally, I prefer the local option because it eliminates any possibility of network trouble interfering with the saving of data. It's very rare to have any trouble, but at least consider how reliable your network is before choosing the common data folder option. Also, if you choose this route, be sure to read the bit about unique machine codes.
You can also see the relevant section from the guide online here:
www.empirisoft.com/medialab/help/preferences.htm#prefs_altdata
Note that, even if you choose the common data folder option, there is still no way to automatically merge the data files. That still has to be done manually in a program like SPSS or MediaLab's FileMerge utility. The only advantage the network folder option gives you is that all your files will be collected in one place (in order to avoid scurrying).
See also:
www.empirisoft.com/support/showthread.php?t=440
www.empirisoft.com/Support/showthread.php?p=4006