Bluepint default property reference

I have to create a skill system in my game.The structure of skill data is like this:

class SkillAction
{

};

class SkillPhase
{

TArray < TSubclassOf< SkillAction > > mActions;

};

class SkillData
{

TArray < TSubclassOf< SkillPhase > > mPhases;

};

When the designer add a mPhases in the class SkillData,he has to create a blueprint of class SkillPhase,and the new mPhases element refrence to it. It’s the same to add mActions in class SkillPhase,so there will be many blueprints created for just a SkillData.It’s very hard to maintain so many blueprints.But In UE3,the same structure can be edited in just one archetype.Is there some good idea to solve this problem.

Is there somebody help me?