Linking sheets which must update the date first.

I have 50 clients, each with an Accounts Recievable worksheet. Past due is
determined by using the =now and =today functions. This information is then
linked to a Master sheet which displays all 50 clients at one time.

The problem is: When I open the Master sheet, the dates on the 50 'feeder'
sheets do not update the date. Only if those sheets are opened does the date
update.

Is there a command to open and close those 50 sheets or a recalculate
command or perhaps, a macro is needed to open then close the 50 sheets.

Any suggestions?

I posted the same question about an hour ago but have'nt seen it appear
here, so if it does, please excuse the duplicate question (albeit, worded
differently)

Bob