How to control two devices with two GPIB-USB-HS+ simultaneously in LabVIEW?

Hi, 

I'm learning how to use LabVIEW to control my GPIB devices. I can find my device in NI MAX and run the examples provided by LabVIEW, "Simple GPIB.vi" and "GPIB with VISA functions.vi". But in these VIs, I can only input ONE GPIB address or VISA GPIB Resource, I tried syntax like "0:1,1:2" to bundle two GPIB devices, but it doesn't work.

I wonder if there are some syntax or functions that could solve my problem, or I have to run two same codes in parallel in order to send message almost simultaneously.

Thank you in advance.