Assuming you are running an Allegro/Presto/Vivace edition, I notify you, just in case, of the
DOCS-SDKs/Clustering.pdf
document.
The clustering is based on the allocation of single streaming sessions on one of the available Lightstreamer Server instance, hence a single client session cannot get data from different Data Adapter instances.

As a consequence, in terms of tcp connections, each streaming connection is issued to the load balancer and entirely forwarded to one of the Server instances.
Note that, once it has been established which Server instance is devoted to a client session, other connections related to the session may be directly issued by the client to the Server instance, depending on the configuration.
Also note that, unless the load balancer prevents it, two different sessions opened by the same client may be forwarded to different Server instances.