Identify which object triggered the Ydoc update event?

On the Ydoc, I have a root YMap with two elements, when I do some changes on either element on the rootMap, is it possible to identify which YMap element triggered the update in the doc.on('update',xx) event?

    const rootMap = this.ydoc.getMap('rootMap');
    // first map element
    rootMap.set('submap1', new YMap());
    // second map element
    rootMap.set('submap2', new YMap());

    this.ydoc.on('update',(update, origin, doc)=>{
      // question here? identify this update was triggered on 'submap1' or 'submap2'?