Virtual assistant - open second and fourth Saturday

In addition to our regular hours we’re open the second and fourth Saturday of each month. How do I put that into the virtual assistant calendar? So far the only way I could figure out was to say we’re open every Saturday and mark the one’s we’re closed as holidays. It’s kind of a pain. At the start of new year I have to clear the old “holidays”, which have carried over by date instead of day of the week/month, then enter all the new ones. There must be a better way.

I know of no other way other than your current work around.