How do I share a new request with a customer group through REST API?

[dan]

I'm trying to create new requests for our Service Desk through the REST API, and I'm having trouble figuring out how to share a request with a customer team/group.

Our request portal seems to have the right 'Share with' option selected by default:

However, when I create a new request through the API the request is only shared with the user doing the API call (myself), and not with the Scalability Team like I was hoping.

I suspect that I need to add the Scalability Team/Group to the 'requestParticipants' array in the API, but I cannot find a way to get the 'accountID' of the customer group/team. Hopefully I don't need to add the accoundID's of the whole team to the participants array!

So what is the best way to do this through the API? Can I get an accountID for a customer group? How do I share requests with customer groups through the API?

Thanks