This is an Excel Macro question, not a java question.
In the sheet you want opened, go to the VBE.
Open 'ThisWorkbook'
Once here, you can select "Workbook" from the Object drop down list, located in the top left of the module pane.
Type
Private Sub Workbook_Open()
and put in the macro call.
Example:
Private Sub Workbook_Open()
Run "Macro1"
End Sub
Then whenever the workbook is opened, the macro will run, regardless of whether it is called by yourself from Excel, by another Excel sheet, or by java etc.
I hope this helps, please vote up if it does!