[schapplm]

I run the following query in the mean time to clear out the watched status: 

sql:
DELETE FROM `episode_watched` WHERE idShow=ANY(select idShow from tvshows where title = "Friends") 

I think the multi user solution would be the better way to go, since this seems to be a very special case to consider in the addon. Neverthess, I added this to the ToDo list of the addon, but it is unlikely I (or someone else) will do this due to time limitations.