Is it possible to block suppliers from accessing supplier portal for specific timeframe?

Summary:

Is it possible stop suppliers from uploading invoices or block them from accessing supplier portal for specific timeframe as it creates issues during AP close?

Content (required):

Would you please create a block which can be turned off and on each month so that Suppliers are blocked from uploading invoices to the Internet Supplier Portal (ISP) during the monthly AP Subledger close? I'm not sure if the entire ISP should be blocked during this time or whether they can only be restricted from uploading invoices.

When suppliers upload invoices in the ISP at the same time we are closing the AP Subledger, it forces us to start the close process anew, as their new invoices would require us to re-Validate and re-Sweep to the next open period and re-do other close steps.