I have a worksheet shared by 6 people at sharespace.
Please let me know how can I control the parallel updates of all in
the sheet.

e.g Let us say all users open up file at same time t. If user 1 make
some change and save it at time t+1.
Then if user 2 is saving it at t+2, updates entered by user 1 will be
missed out.

Please advise how can I manage this using macro or sharing control.

regards
sanjay