Javascript 在Angular 2 MultiSelect下拉列表中禁用标题单击分组

我使用的是angular 2 multiselect，我想在选择组时禁用标题单击。我需要分组只是为了逻辑分组而不是选择，所以请建议如何禁用标题单击，它不应选择子项

这是我正在使用的插件

<angular2-multiselect [data]="otherSkillList" formControlName="otherskills" [(ngModel)]="selectedotherSkill" [settings]="otherSkillSettings" (onSelect)="onOtherSkillSelect($event)" (onDeSelect)="onOtherSkillDeSelect($event)" (onSelectAll)="onotherSkillSelectAll($event)"
                            (onDeSelectAll)="onOtherSkillDeSelectAll($event)">
                        </angular2-multiselect>


this.otherSkillSettings = {
  singleSelection: false,
  text: 'Select ' + this.adminPage.OtherSkillsOtherServices,
  enableCheckAll: false,
  enableFilterSelectAll: false,
  searchPlaceholderText: 'Search ' + this.adminPage.OtherSkillsOtherServices,
  enableSearchFilter: true,
  badgeShowLimit: 5,
  limitSelection: 8,
  groupBy: "category",
  disabled: false
};