Google calendar setup with multiple Service Providers


We have setup the GCal integration within Appointments+ and are trying to get it working with multiple service providers, each with their own Google Calendar account/ID.

From testing it appears that the plugin will only handle one private key file and Google API email address, so we have created a main Google API account for use across all Service Providers, with the intention that they will each have a separate calendar with a unique ID.

However, the plugin only sends the appointment information to the calendar ID specified in the main backend, not the calendar ID specified in the API section of each Service Providers profile. This happens even if the backend is set to only send to the main ID when no Service Provider is specified.
Removing the API/ID information from the main backend results in Google Calendar integration not working at all.

Is there any way for the plugin to use the calendar IDs or API information in the individual Service Provider profile pages instead of being overridden by the main section? We do not especially need the main section to integrate at all, but this issue happens whether or not the main section is set to integrate.