Enquiry about EV roaming/OCPI

Hi everyone!

I know this is out of context, and it's mostly related to in-depth EV technology.
I have been working on EV technology for the past 3 months as a developer. I could able to do an OCPP connection which is, I could able to connect to the firmware of charging stations and could able to get the data in my backend server. 

Now the challenge I'm facing is to do an EV-roaming connection. I have 2 different tenants or you can call them sites. evion.quantumccharge.in as (eMSP - e-Mobility Service Provider) and ite.quantumccharge.in as (CPO-charging point operator).

To reference, I'm using this open-source project from GitHub, which has most of the functionalities of EV([OCPI-open charge point Interface],[OCIP], etc..).
https://github.com/sap-labs-france

    

<-- This is what I was trying to do, to connect through interoperability in ite.quantumccharge.io, where I trying to take the local token from evion.quantumcharge.io and trying to add it to ite.quantumcharge.io's remote token and vice-versa.
Where URL, I was trying using to backend server URL to fetch the endpoints of each other.
But that doesn't seem to work. I need your opinion of what URL should I have to use to connect the two tenants to each other, so that eMSP can use CPO's charging stations as roaming. Do you think should I use the tenant's IDs to connect each other?

Thanks in advance. If anyone can help. I'll be very grateful.