relative-guard-3.ts

import { Injectable } from '@angular/core';
import { ActivatedRouteSnapshot, createUrlTreeFromSnapshot } from '@angular/router';

@Injectable({ providedIn: 'root' })
export class MyGuard implements CanActivate {

  canActivate(route: ActivatedRouteSnapshot) {
    if(checkData(route)) {
      return createUrlTreeFromSnapshot(route, ['../sibling']);
    }
    
    return true;
  }
}