Nice Idea but most 911 centers in the US don't just do EMS dispatchers any more, they have been training most EMD certified dispatchers to do all around dispatch and rotate them throughout the center to try and prevent burnout. Don't know if you want to try and incorporate that into it with police and fire. You see this more with bigger cities and county run dispatch centers. Some small towns still do the main 911 call in then transfer to the appropriate dispatch for need IE police, fire, ambulance. Also to think about with medical is the EMD dispatching system which is used more widely in the US and is basically a Rolodex of cards with questions that have to be asked which leads to the appropriate dispatch EMD code. This tell you weather to dispatch BLS or ALS in a Alpha, Bravo, Charlie, Delta, Echo and omega. Alpha being BLS lights and sirens ALS if sent no lights and sirens, Bravo BLS lights. Charlie BLS lights and sirens ALS lights, Delta BLS and ALS lights and sirens, Echo everyone lights and sirens and usually a fire rescue as well most likely being a active CPR. Omega is usually if used a non emergency call someone needs help getting up elderly needing help with home O2 ect.. Would love to help but not familiar with coding or HTML I am a former firefighter EMT out of Delaware I could help if you have questions on how my area dispatches ect.
Could also do something along the idea of integrating something into LSPDFR for role playing clans don't know how it would work but maybe something along the ideas if we ever get MP they push the callouts out...ect.