Tag the first Space, then use the Multiple option (look at the prompt on the command line) and select all of the Spaces to which you want add tags.
Thanks for that to the point answer.
A half hour of searching "help" netted me not a clue on how to do this.
Really a simple search "tag multiple spaces" Should get you to somewhere that tells you how to tag multiples spaces. Instead the frist result is for Attribute Definition Dailog Box, which has nothing to do with tagging spaces. Please somebody fix the help indexes before it too late!