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I have a spreadsheet that contains a list of vehicles that we have in stock. All our sale staff have access to this sheet. We have the sheet locked down so they can only edit certain columns. They have to be able to add information if they have a potential buyer for a certain vehicle but only in a certain column. The rest of the sheet is locked down so they cannot edit anything. Problem being is that now only one person can be in the sheet and editing it at one time. So if someone else needs to get in and edit it they can read only access to the sheet.

Is there any way to get around this so any number of people can access and edit the sheet at the same time?