Get team assigned to issue from an event webhook

Hey, I already have a webhook, sending all events from my project to a serverless function, that dynamically posts to the appropriate slack channel.

How would I find which issue is it from? And the assigned team/user to it?
I’d like to post errors to the channel of the correct team!

What I am trying to achieve:
With the new slack integration, we can easily assign the team responsible for one issue directly in slack. So I want to post all issues not yet assigned to one generic channel, and as soon as someone assign it, the next should already go to the correct team/channel.