如何在我的formBuilder.group中使用两个组验证Angular 10+中的反应式表单

import { FormBuilder, FormGroup, Validators } from '@angular/forms';

constructor(private formBuilder: FormBuilder) { }

ngOnInit() {
  this.myForm = this.formBuilder.group({
    group1: this.formBuilder.group({
      field1: ['', Validators.required],
      field2: ['', Validators.minLength(5)]
    }),
    group2: this.formBuilder.group({
      field3: ['', Validators.pattern('[a-zA-Z]*')],
      field4: ['', Validators.email]
    })
  });
}

<form [formGroup]="myForm" (ngSubmit)="onSubmit()">
  <div formGroupName="group1">
    <input type="text" formControlName="field1">
    <input type="text" formControlName="field2">
  </div>
  <div formGroupName="group2">
    <input type="text" formControlName="field3">
    <input type="text" formControlName="field4">
  </div>
  <button type="submit">Submit</button>
</form>

onSubmit() {
  if (this.myForm.valid) {
    // 执行提交操作
  } else {
    // 处理表单验证失败的情况
  }
}