How to extract connections from architecture ports in a System Composer Mapping block

Hi everyone, I have question regarding architecture ports and dot notation for buses. I have a simple architecture, and I want to create an Input/Output excel file automatically through a Matlab script.

My problem is that I cannot find a way to get which PDU inside the CAN1 bus is connected to which PDU in CAN2. This is, I cannot get the connections I made inside the MappingBlock. Through Matlab commands I am able to get all the ports and all the components, and inside I can see the connections between CAN1 and the CAN2 PDUs, but not the specific CAN1 PDUs that are linked to the ones in CAN2. Also I am able to see which CAN1 PDUs are selected, however not to which CAN2 PDUs they are connected. Could you help me with this?

modelName = "Arch";
model = systemcomposer.openModel(modelName);
arch = get(model, modelName);
load_system(modelName);
open_system(modelName);
MappingBlock = arch.Components(1,3);