You can use the Map Compare function for this. Enter your name in the profile name box and then click the list icon in the right end of the compare with field ("multi compare"). Now you can enter several other cachers to compare with. You can then also enter any other search criteria, like a radius filter (see under Add filter). Use the None found, One+ found and Everyone found checkboxes to determine if caches unfound by all of you, some of you or none of you will be shown.