Zapier integration: posting to Slack

I’d love to integrate our company P2 into other apps. Most importantly, that would mean having automatic posts to our company Slack when a new post goes out. It seems that for this it is necessary to have the zapier plugin for wordpress. However P2 doesn’t seem to allow plugins (for good reasons I’m sure, as the wide world of wordpress plugins would certainly be too broad) – but is there another alternative to achieve what I’m trying to do? Thanks!