create additional validation on the form registers the default laravel

This users(mstanggota) table:

 Schema::create('mstanggota', function (Blueprint $table) {
            $table->increments('id');
            $table->string('no_anggota',10);
            $table->string('name');
            $table->string('email')->unique();
            $table->string('password');
            $table->rememberToken();
            $table->timestamps();
        });

Mstbeasiswas table:

Schema::create('mstbeasiswas', function (Blueprint $table) {
            $table->increments('id');
            $table->string('no_anggota',10)->unique();
            $table->string('nm_anak',25);
            $table->string('kt_lahir',25);
            $table->date('ttl');
            $table->String('nm_skl',50);
            $table->String('st_pend',6);
            $table->String('lbg_pend',6);
            $table->String('prov_skl');
            $table->String('jenkel',9);
            $table->integer('k_umum');
            $table->integer('k_khusus');
            $table->integer('score')->nullable();
            $table->boolean('status')->default(0);
            $table->string('ket',250)->nullable();
            $table->string('img1',50)->nullable();
            $table->string('img2',50)->nullable();
            $table->string('img3',50)->nullable();
            $table->timestamps();
        });

I would like to make an additional validation. If no_anggota does not exist on table mstbeasiswas then the user cannot register, what is there that could help me? :(

register form view->

via Chebli Mohamed