The object libraries can be stored on a network folder for sharing.
1) The default location for the object libraries on Windows 7 for user 'sw' is C:\Users\sw\AppData\Roaming\Adobe\Designer\9.0\EN\Objects. Copy the libraries to a network share, for example Z:\Adobe\Designer\9.0\EN\Objects.
2) In Designer go to the Object library. For each group you want to share click on the list icon highlighted in orange, below.
3) Select Group Properties from the drop-down.
4) Change the location to point to the network share.
Steve