does the tags not already try to autocomplete.. its been a minute since i used it.. if so do you actually need to havea fixed list
and the answer i think is yes but its not straightforward
catch add event and then run your own ode to find the tags and then use the contentservice to update the required properly..
thats the "simplistic view" but does not tell the whole story
I also feel the phrase what version are you running and working in needs to be asked??