How to specify Chat Integration Id in Chat APIs so that session/engagement created lands up on specific Integration Id

I have created a Chat Integration Id using Default Connector Type on my AXP Tenant: FCFSRQ

While using Chat APIs via Postman to create a chat session/engagement, I could not find any specific path or body parameter to ensure that the resultant engagement lands up on the above Integration Id that I have created. Earlier I thought ChannelProviderId would be the parameter which needs to be assigned specific Integration Id value for this to happen.

However regardless of any value (including random value) passed to ChannelProviderId, the resultant engagement/session always lands up at custom Chat Integration created by someone else on my tenant using Chat Connector type.

How can I test Chat APIs via Postman against my specific Chat Integration Id which I have created on my tenant?