Hopefully this screenshot of my setup will help clear things up:
Node 26 is a red series dimmer
Node 31 is the physical (root) device of the LZW36
Node 31.1 is the Light endpoint of the LZW36
Node 31.2 is the Fan endpoint of the LZW36
In order to control just the light endpoint of the LZW36, I have to send commands to node 31.1. If I send a command to Node 31 (without the endpoint after the decimal), it will control both the fan and light at the same time.
Since the Red Dimmer does not support multi-channel (multi-endpoint) association, it is not able to send a command to endpoint Node 31.1, and will instead send the command to root node 31 (which controls both the light and fan).
The only solution I am aware of is to use scenes and have the hub send the command to the proper endpoint