RT-AC2900 NAT LOOPBACK

Dear all,
please tell me if merlin firmware supports NAT LOOPBACK for RT-AC2900(RT-AC86U)
If not a new maybe an older.
I am not an IT specialist.
How i can do this with simple steps if your firmware doesnot support it.
Original asus firmware does not support NAT LOOPBACK
This is the official answer from ASUS today.

thanks in advance
Nick