如何在Laravel中将三个多对多关系结果组合到一个集合中？

public function roles()
{
    return $this->belongsToMany(Role::class);
}

public function permissions()
{
    return $this->belongsToMany(Permission::class);
}

public function users()
{
    return $this->belongsToMany(User::class);
}

public function permissions()
{
    return $this->belongsToMany(Permission::class);
}

public function users()
{
    return $this->belongsToMany(User::class);
}

public function roles()
{
    return $this->belongsToMany(Role::class);
}

$user = User::with('roles', 'permissions')->find($userId);

$combinedRoles = $user1->roles->merge($user2->roles);
$combinedPermissions = $user1->permissions->merge($user2->permissions);