There's not a way to manage staff members AND rooms in Full Slate. We've seen businesses take several approaches to handle this situation:
1) Set each staff's availability such that there are never more staff members working than there are rooms. So, if you have three staff members and two rooms available, then ensure no more than two staff members have availability at any given time. You can control staff availability using the 'Change hours' feature on the Schedule tab: http://support.fullslate.com/hc/en-us/articles/201009788.
2) When a new appointment is scheduled, block out time on the other staff schedules so that a double-booking cannot occur. The downside to this approach is that you must manage your schedule very closely to ensure you quickly block out time after each appointment is booked.
3) Set up your rooms as resources under Setup > Staff rather than your staff members. That way you'll only have availability for each room. The disadvantage of this approach is that clients cannot schedule appointments with specific staff members and it may be more difficult for staff to manage their schedules.
4) If there's only two of you, you can set up a Webcal subscription from Staff 1 to Staff 2, and vice versa. A subscription can take up to six hours to update automatically, but can be manually updated by going to Schedule > More > Sync now. First, go to Schedule > More > Sync, import, export and "View your Full Slate calendar in another application." Copy/paste the Webcal URL's for both of the staff schedules you want to connect. Then, go back to Schedule > More > Sync, import, export and choose "Synchronize Full Slate with an external calendar." Click "Add connection" then "Subscribe to another external calendar." Subscribe Staff 1 to Staff 2's webcal URL. Repeat for Staff 2 and subscribe that staff to Staff 1's webcal URL. The events booked onto each staff will then update onto the other staff schedule in a read-only format (to block off time) within six hours. (If you have any trouble setting this up, please contact us at firstname.lastname@example.org and we're happy to set this up for you)
We plan to add 'resource' functionality in the future, though it's not currently on our short list of projects.