Options binding to custom repeater attribute

Framework Knowledge
1

What is the correct way to add options binding to custom attribute that overrides repeater?
For example in bcx-aurelia-reorderable-repeat package there is the following syntax:

<div reorderable-repeat.for="item of items" reorderable-group="${group}">${item}</div>

reorderable-repeat uses the following code to get reorderable-group value:

  _reorderableGroup() {
    if (this.viewFactory && this.viewFactory.viewFactory) {
      const node = this.viewFactory.viewFactory.template.firstChild;
      const targetId = node.getAttribute('au-target-id');
      const instruction = this.viewFactory.viewFactory.instructions[targetId];
      if (instruction) {
        const bi = instruction.behaviorInstructions.find(bi => bi.attrName === 'reorderable-group');
        if (bi) {
          const exp = bi.attributes && bi.attributes['reorderable-group'];
          if (exp && typeof exp.createBinding === 'function') {
            // binding expression or interpolation binding expression.
            return exp;
          }
        }
      }
    }

    return this._getPlainAttribute('reorderable-group');
  }

But the above code fails when repeater is combined with custom attribute, that changes context. For example reorderable-repeat.for do not work together with with.bind:

<div reorderable-repeat.for="item of items"  with.bind="item">

because it can’t get the value of reorderable-group using node.getAttribute('au-target-id') technique