Passing Variables between Templates

Hi I have this loop setup in my html like so:

{{#each group}}
  {{with event this._id}}
       <p>{{title}}</p>
      <p>attending: {{respondingMembers _id}}
         {{#if moreThanOneGroup}}*{{/if}}
      </p> 
  {{/with}}
{{/}}
respondingMembers(callid) {
    // get attending members
	let responses = _(Response.find({callId: callid}).fetch()).reverse()
	let group = Template.instance().group.get()
    let members =  Members.find({ _id: responses[0].memberId, brigade: brigade}).fetch()
	let uniqueMembers =  _(members).uniq()
    // check uniqueMembers against an array of attendingMembers if not in attending add them to attending if in attending set moreThanOneGroup to return true
    return uniqueMembers.length
  },
moreThanOneGroup() {
		return 
}