You should wait and see whether or not the agency will be issuing a radio for duty use before committing to buying a radio. If they do not issue you a duty radio and require that you purchase your own (which is questionable), then you will want to consult whoever coordinates your radio system on what kind of radio will suit your purpose. If you are seeking to purchase this radio for personal off duty use, then you should consult the department SOPs and administrative personnel regarding policies of radios off duty. The database shows a mixture of many different radio systems that will make it hard to say which kind of radio you will need. A multiband radio will allow you to do this, but will cost thousands of dollars. If it ends up being some type of digital radio, then you will be required to go through official channels to obtain the necessary keys for the radio system to gain access.
If you intend on only listening to neighboring channels to hear what is going on, then many users (including those involved in public safety) have gone the scanner route as it provides the widest amount of coverage for the price. They will not allow you to transmit, but you shouldn't be needing the ability to transmit on those channels while not on duty.