[Discuss-gnuradio] GRC with 2 USRP X310 motherboards and 4 channels

[Trek]

I need to set up 2 X310 motherboards to do a 4 channel receive using Gnuradio-Companion under Ubuntu 14.04 LTS,

Under GRC, it seems not straighforward to specify the four different carrier frequencies (all four channels have different center freq). 

Pl. help. 

Thanks,