Check out this example google spreadsheet

The top of each column is a sort key. Not quite what you need.

What I think you are asking for is a ranking formula that boils down to "Days since hosting a guest". It would need to use the (current date) - (date found by finding the last entry on row and using that cell location to lookup the date of that meeting) basically it's just the same as you would do manually, but written with excel functions. Then sort the table by the value of the ranking formula.