Thanks. So, it looks like the only way to really do this would be to make a separate API call for each Topic.
I wouldn' t worry too much about that second call, I tested batch queries a lot in terms of performance and unfortunately the performance gains are minimal to negligible, the API calls are still made, for large and nested collections maybe a bit more efficiently than if you would do it in FreeMarker with a loop, but in my experience FreeMarker hasn't been the bottleneck (most of the time) but the API's response time is and that doesn't change with subqueries.
Oh, that's interesting. Right now, with the replies subquery it loads very quickly, so I will try looping through and making the additional API call instead. I assumed it would take forever but if the speed is similar to the subquery that might work.
Thanks
