The Solace Javascript API does not support Selectors. You can see that in the matrix table at the bottom of Solace PubSub+ Messaging APIs
Is it possible to add more queues? The magic of pub sub and publishing to topics (instead of queues directly) is that you could add a new queue that only receives 1 of the 6 topics and consume directly from that… same with the other 5. And you can do that without changing your publishers or even the contents of the original 6 subscription queue.
Also, with the PubSub+ architecture, that wouldn’t be double the storage consumption as the broker only keeps 1 copy of each message in the spool and it can be referenced by many separate queues.
The only “cost” is 6 queues, 1 for each subscription, which sounds like it ideally suits your use case. Even if JS supported selectors, I think the 6 queue solution is much better for you as there would be no performance penalty.