How can I monitor multiple specific Slack channels without using ‘Watch Whole Workspace’?

Based on the current documentation for the Slack Trigger node, the node only supports monitoring a single channel when you disable the "Watch Whole Workspace" option. In other words, you cannot specify multiple channels or pass a comma-separated list of channel IDs in one node if you don't want to watch the entire workspace.

This is due to two main reasons:

1. Single Webhook Limitation:
   Slack only allows one webhook URL per app. If you try to have multiple trigger nodes (each with different channels) using the same Slack app, they will conflict because Slack sends events to the single registered webhook URL.

2. Channel Parameter Limitation:
   When "Watch Whole Workspace" is turned off, the node’s "Channel to Watch" parameter is designed to accept only one channel at a time. This limitation prevents you from monitoring multiple channels using a single instance of the node.

Workarounds

• Use Watch Whole Workspace and Filter:
  You can enable "Watch Whole Workspace" so that all events reach the node, and then use additional nodes (e.g., a function or IF node) to filter the events for the specific channels you are interested in. This approach, however, will incur processing of unwanted events which might not be optimal if you’re trying to control costs.

• Separate Slack Apps for Each Channel:
  If you really need dedicated triggers per channel without picking up extra events, consider creating separate Slack apps. Each app would have its own webhook URL, allowing you to set up multiple Slack Trigger nodes that monitor individual channels. Keep in mind that this approach increases the management overhead on the Slack side.

These limitations and workarounds are outlined in the documentation for the Slack Trigger node. Let me know if you need more details on configuring any of these solutions!