Managing Alertts on Sharepoint

as the Administrator of our Sharepoint site, I am wanting to set up alerts for all users so they are notified when lists are updated.

I am doing this is administrator to be sure Users are kept aware of changes. I am trying to do away with the emails to let Users know information as been updated.

I have found i can add these alerts, however, i am finding that i have to enter a user, not a group. When i do a group, Sharepoint says it can not find email addresses. Maintaining this would be a nightmare.

Any help would be great.