Go to the Filters and Blocked Addresses tab in the Gmail account settings page.
Select Create a new filter from the bottom of the page.
Here you define the search criteria for your new filter. If you are forwarding a dispatch related email that is coming from a static email address, just enter that email address into the From field.
After entering the desired search fields, select the link in the bottom right hand corner of the screen, Create filter with this search >>.
This is where you specify what you want Gmail to do with the filtered messages. To forward this message, select the box for Forward it to: and then choose your Active911 alert email address.
Once you have all the options you would like selected (forwarding, labeling, deleting, etc), click Create filter.
This will take you back to the Filters and Blocked Addresses tab where you can view and edit these filters anytime you wish.