And that's why you work where you do. Good solution. I tested it out and it does what I need and haven't noticed any immediate side-effects. I, almost universally, desire the behavior on only those groups that target a single property so all I had to do was adopt a naming convention for those groups.
public void PostProcessObjectFactory(IConfigurableListableObjectFactory Factory)
string ValidatorGroupNames = Factory.GetObjectNamesForType(typeof(ValidatorGroup));
foreach (string ValidatorGroupName in ValidatorGroupNames)
IObjectDefinition definition = Factory.GetObjectDefinition(ValidatorGroupName);