groov can support many video cameras on the one page. Just be sure and use sensible refresh rates.
Also, it might help if the refresh rates are different. (Hint, try and use prime numbers for the refresh rate for each camera so they do not all try and update at the same time).
No, groov does not support sound at this time.
You could set up a notification so that the user gets an email. Your phone or computer could be set to make a sound when an email comes in..... Just a thought.