Is it possible to extend custom types?

This is a use case that I have:

{
  "title": "ILinkProps",
  "$schema": "http://json-schema.org/draft-04/schema#",
  "type": "object",
  "extends": {
    "$ref": "#/definitions/anchor"
  },
  "properties": {
    "visited": {
      "type": "boolean"
    },
    "external": {
      "type": "boolean"
    },
    "icon": {
      "type": "boolean"
    },
    "to": {
      "type": "string"
    },
    "component": {
      "$ref": "#/definitions/component"
    }
  },
  "definitions": {
    "component": {
      "tsType": "React.ComponentClass | React.SFC"
    },
    "anchor": {
      "title": "Anchor",
      "tsType": "React.AnchorHTMLAttributes<HTMLAnchorElement>"
    }
  },
  "additionalProperties": false
}

Expected Output:

export type Component = React.ComponentClass | React.SFC;
export type Anchor = React.AnchorHTMLAttributes<HTMLAnchorElement>;

export interface ILinkProps extends Anchor {
  visited?: boolean;
  external?: boolean;
  icon?: boolean;
  to?: string;
  component?: Component;
}

What I get instead:

export type Component = React.ComponentClass | React.SFC;

export interface ILinkProps extends Anchor {
  visited?: boolean;
  external?: boolean;
  icon?: boolean;
  to?: string;
  component?: Component;
}
export interface Anchor {
  [k: string]: any;
}

Is it possible to have the generated interface extend custom types?