HME DX-210 vs 2x RTS Party Lines


I'm a happy user of HME-DX210 wireless intercom system with 4 beltpacs. 
Today I need to connect two different RTS intercom channels (different XLRs) to two 2-wire inputs of my HME base station. 
I would like, that every wireless user can listen/speak to IC1 or IC2. I need users of IC1 group not to hear IC2. 
I connected two XLR cables from 2-channel RTS base station to two my 2-wire inputs, connected wired beltpacs next to HME station. I pressed 2-wire mode to RTS, selected both 2-wire inputs on front panel. Everything looks good, BUT HME station merges both inputs. I hear both wired channels in IC1 and IC2. 

Please, help me solve - what is wrong... I need isolated IC1 from IC2. 


In RTS mode the intent is that you use a single XLR cable from your RTS to connect to the IC1 port. From the front panel of the DX210 engage the 2 wire circuits on both IC1 and IC2. You now can hear both channels of the connected RTS system. Channel A on IC1 and Channel B on IC2. The IC2 port at the rear of the DX210 can now be used to daisy chain in an additional RTS beltpac. You can not bridge two different RTS systems through the DX210 base and maintain intercom channel separation between both systems.