A simple macro like this should work. The macro would reside in the master
and would be run after you've updated the master. The links should update
automatically.

Sub UpdateLinks()
'Update First Workbook
Workbooks.Open Filename:="C:\Sub1.xls"
ActiveWorkbook.Save
ActiveWindow.Close


'Update Last Workbook
Workbooks.Open Filename:="C:\Sub2.xls"
ActiveWorkbook.Save
ActiveWindow.Close
End Sub