Hello Songgoon,
please refer to figure 1. in the NVT2002 datasheet. The A1 and A2 can be used independently. Only dependence is between the A1, A2, B1, B2 and the EN pin. If the pin is held low, the four pins are in high impedance state.
JozefKozon_0-1633087314521.png
JozefKozon_1-1633087346556.png
With Best Regards,
Jozef