Hi together

I was trying to set up a GroupWise rule that only replies to mails on fridays. But I cannot find any contitions to set that up.
This is because a customer of me is working parttime and don't want to activate/deactivate every week the "out-of-office"-rule.

First Question is: Is it possible?
Second Question is: How can i set that rule up?

Thank you in forward for the help.

Best Regards
Michael