short answer: at the moment no. if the respective file is written from excel, there is an excellent solution here: http://liquidtectonics.blogspot.com/2009/01/grasshopper-excel-part-2.html
See this thread for further details about streaming live data: http://groups.google.com/group/grasshopper3d/browse_thread/thread/54bf3e0f018b099a/7310b5e84142adb7?lnk=raot#7310b5e84142adb7 and/or search the group, there's been more chatter about this...
