Is there a way of increasing the number of “recent rooms” in the Outlook for Mac Scheduling Assistant to reflect more than just 4 recently used rooms?

We have around 12 meeting rooms in our business. Every time I want to check room availability I have to manually add each room until I find a free one.

It would be much simpler if all 12 rooms were visible in the "Recent Rooms" section of the Scheduling Assistant - however this section only seems to reflect the 4 most recently used rooms.

Is there any way around this problem?

Thank you

Jean