Frustrated PA!

Hi ill try to make this simple.
I manage three people calenders as well as my own.
All meeting requests are fwd onto my inbox for me to advise and reply
availability.
I have set up a folder for all meeting requests to go to my meeting request
folder.
I would like to be able to sort 'somehow' by the person needed for the
meeting, ie divide all of person 1's meeting requests from person 2 and 3's.
I dont mind how i divide/sort these, whether its by folder or colour or a
simple sort within a folder.
One issue i cant seem to get around though is the fact that 20% of the time
these three people are all requested for the same meetings.

Please help a frustrated PA.

thanks