AP_Periph with multiple Rangefinders setup?

Hi all, I have play around with AP_Periph. I use a flight controller(F7 base FC) as node. I want to attach 2 RFDs. but only one is working. Is it only one rangefinder support at latest firmware?
I still fly 4.0.6 (native CAN not support). but I want to use CAN radar. so I thought I could attach 2 CAN radars to AP_Periph. currently one is working. maybe I miss something?
P.S. I had modified Benewake_CAN driver to work with CAN microwave radar from another vender.