Hi John,

There is a powerful feature 'Skin Inheritance' thats got introduced in 7.2 .

For our skin , we can add  parent skin(s) so that all the mixins and formats from the parent skin got inherited by our skin. And we can override or delete the mixins/formats. Even stylesheets also got inherited by our skin. 

In skin rule, there is a 'Inheritance' tab ,so that we can add  parent skins . 

This capability is available from 7.2 .