check box to check all in continuous subform

[deb]

I am using John Viescas Inventory database. Great database.
frmVendorInvoices is the form and fsubVendInvoiceProducts is the continguous
subform.

fsubVendInvoiceProducts has 3 check boxes.

I want a check box to check or uncheck all of the field instances of
"Invoices" in the continguous form. I do not want the other two check boxes
to be checked, only the Invoices one. However, since it is a continuous form
I need all instances of the Incoices check box to be checked/unchecked.

Thanks