Help with Paradox alarm system & Home Assistant

Hi
I am new member and in general a noob to arduino and home assistant.
I have manage to connect my SP6000 paradox system to Home Assistant using this guide

I am also using this device (Trikdis G16) in order to have an extra layer of security. It is a GPRS module to send the messages in security center.

My problem is that both of the devices in order to work must be connected to the 4 pins serial of the paradox alarm, but only one is available. I am looking for a solution and hope there is. Do you have any suggestions,ideas?

Thanks