It would be handy if there was a feature (perhaps a premium/paying feature), that you can specify a challenge checker and specify a set of coordinates and the feature would return a list of the nearest 10 geocachers that meet the requirements. Or, maybe list up to 20 in ascending distance order, so that one could choose among the list for other criteria. This would be useful if a geocacher would like to hide a duplicate to that challenge in their area (at the given coords) and needs to provide the reviewer with a list of 10 area geocachers that qualify. I know you can check individual geocachers names for each checker, but for more challenging challenges, you might have to check dozens to even hundreds of likely geocachers and might not remember to check a few that do qualify. I know Project-GC is constantly checking all premium/paying members to see if they qualify for challenges, so I assume getting a list of those premium members that had qualified for a challenge would not be a big processing hog. I do not know if it also checks the non-premium members automatically (and just not allow them to know), or if this process would need to do a check for each non-premium members on the fly. If the later, that would be a good reason to make this feature a paying member feature.