Raygun allows you to merge distinct error groups into one. This can be useful when similar errors are treated as unique by default.
On an application's error dashboard simply tick the box beside two or more error groups you wish to merge then click the "Merge" button which appears above.
You will then be prompted to select which of the error groups the others should be merged into.
After merging both types of error will now appear under the new merged group and any reoccuring errors will appear in the new merged group.