How to prevent submitting if condition not fulfill

Is there a way to prevent the form from submitting if they have less than 4 cameras? I can hide the submit button but I'd rather show the "the minimum total of cameras is 4" message instead so it will be more obvious to the customer.

To prevent the form from submitting if they have less than 4 cameras, I strongly recommend you to hode the submit button, however the message "the minimum total of cameras is 4"will be displayed.

The conditions are the following:

When click Next button, the following screen will pop up:

I hope this solves the issue.