A new update for Google Classroom is rolling out over the next couple of weeks.
It will allow teachers to schedule posts across multiple classes in Google Classroom.
Once set, you'll be able to select which classes should receive the post and when it should be published:
Published immediately
Published at a certain time
Save as draft
Please note:
Once an assignment has been scheduled, teachers can change the assignment within each individual class.
Selecting “Copy settings to all” will delete any previously-entered settings for the assignment.
The GIF below shows the process; it does take a second to load:)
GIF showing Scheduling to Multiple Classes in Google Classroom
(More info is available HERE along with the GIF if the one above doesn't load for you.)