Well I've met some situation like this, and used something like this:
So you may a change a context on the element where you want to have callback:
- {{#id}}<a can-click="{{callback2}}">{{name}}</a>{{/id}}
This is not a general case but
actually you have to adjust your design for abilities of the
framework, it usually allows to have elegant solution for any case,
you just have to figure it out.