This is supported in IC614 too (not that there is any good reason to keep using IC614 now; IC615 doesn't require a database migration, and IC614 has not been supported for some considerable time now). Connectivity->Nets->Save All Mark Nets.
You could of course do it using your favourite physical verification tool to extract the net and then save the shapes to a database. You can do this with Diva, Assura, PVS, Dracula, Calibre etc, etc.
Mark Net may be sufficient - it depends on how big the cellView is. You may also need to set up Mark Net "Stop Layers" (hit F3 once you start Mark Net) to stop it marking the connectivity between source and drain under the gate.