Connecting Apartment Doorbell

Hey everyone, I just got a Ring Intercom and am pretty happy with it - almost. I connected it to my TCS ISH1030 Intercom. I’m living in an apartment. There´s a bell at the houses’ entrance door and one at my apartment door. The one at the main entrance is controlled via BUS (a and b clamps) and is working perfectly fine. I used the standard installation as suggested by the app (cable set B with the two BUS cables, see the attached image). The bell switch right at the apartment door is controlled analog (E clamp). Due to missing instructions in the app setup I didn´t connect it yet and it´s not working with the Ring Intercom. Is there any way or workaround to get this one working as well?