allow connecting more distant elements to the same toggle

[dbaron]

There are use cases for connecting more distant elements with the same toggle. For example, typical tab component markup might look something like (in very abbreviated form, with names I just made up):

<tab-view>
  <tab-strip>
    <tab/>
    <tab/>
    <tab/>
  </tab-strip>
  <panel-set>
    <panel/>
    <panel/>
    <panel/>
  </panel-set>
</tab-view>

With this sort of markup, it's hard to model the three tabs using three separate toggles, each with two states, connected into a toggle group. (They could be modeled as a single 3-state toggle, but that has disadvantages, particularly when reordering, adding, or removing tabs.)

It would be desirable to have a way to use a group of 2-state toggles for markup like this.