Does anyone have any suggestions on how to hold Macro running until specific
file being updated?

When I run a Macro, in the middle of the process, I would like to hold Macro
running until the periods between the last updated time for specific file and
the current time is less than a hour.
For example, a Macro is running under the Eric.xls

Sub temp()
Application.DisplayAlerts = False

Workbooks.Open Filename:="C:\A.xls", UpdateLinks:=3
Workbooks("A.xls").Close savechanges:=True

Before processing the next step, I would like to check the last updated time
for specific files - Mary.xls with the current time. If the difference
between the last updated time for Mary.xls and the current time is less than
1 hour, then process the next coding, else wait until the difference periods
is less than 1 hour.

Workbooks.Open Filename:="C:\B.xls", UpdateLinks:=3
Workbooks("B.xls").Close savechanges:=True

End Sub

Does anyone have any suggestions?
Thanks in advance for any suggestions
Eric