Controling avatar's editing previledges

Hello,

I would like to build a space that prevents editing concurrency. In other words, I would like that the "owner" of that space (the user of the machine where that space is stored) can decide the order by which each other user's avatar edits an object in that space.

I am reading the programmer's manual but I still lack the information I need. Does the TSpace have a variable where I can see/get the information on the avatar's visiting it? If it does, can I clearly separate the owner's avatar from the other ones (i.e. to know which is the space owner's avatar)?

I have tried to see each object in the TSpace's #frameChildren. (space frameChildren do: [: each | Transcript show:each] ).
I could have swore that in past experiences I could see the user's avatar in this list (ie: the avatar's Tframe as a child of the TSpace) but as I do this experience now, no avatar object appears.

Any suggestions?
TIA,
Filipe.