Assign message to a specific channel in 8-channel gateway

I was wondering if an outgoing message from node can be assigned to a specific channel within an 8-channel gateway? So I have the 8-channel gateway setup. I would like assign each message going from the node to a specific channel by scripting it in some way. Is there any such possibility?

Could you share the use-case for this? I’m not sure if I fully understand your question.