How to extend rather than replace parent Parameters?

Question

I've got a resource with multiple parameters, and a single action with one extra. How can I write this with the minimal repeats?

Something like this, but that actually works:

## Items [/item{?type}]

+ Parameters
    + type (enum[string], optional)
        + Default: foo
        + Members
            + foo
            + bar

### List [GET {&from}]

+ Parameters
    + page (integer, optional)
        + Default: 1

All other actions should list type, while the GET should list both type and page.