Yes!
You can use single guide on multiple subdomains.
Follow the guide below;
Make sure UserGuiding container script installed on all subdomains.
Go to your guide's settings page and scroll down to Targeting section.
Set a targeting configuration that contains all subdomains.
Example [1]
AAA.mydomain.com/guide-page
BBB.mydomain.com/guide-page
Example [2]
https://prefix-AAA.mydomain.com/guide-page
https://prefix-BBB.mydomain.com/guide-page
That's all!
The guide will work on all sites matching the targeting condition. When you update the guide, it will be updated on all the subdomains.