Quite aware what a rid is as I have been logging and assigning aliases for many years.
If 2247 is the rid/uid of the radio, that's the number you add to your scanner and assign the alias to.
If 2247 is what the units calls themselves on the air, (the alias you want) then the hex/dec number that comes up on the scanner is what you enter and assign the alias to.
I suggested the wiki as there are systems in there with uni/rid info. If you don't see your system in either of theses two searches, then its possible nobody has created a list. That info is all user submitted and quite tedious to maintain. If these searches yield nothing, try searching the name of the system or agency in the wiki.
rid wiki search
Search results for "rid" - The RadioReference Wiki
uid wiki search
Search results for "uid" - The RadioReference Wiki
If there is nothing at all, you will have to do as the rest of us do and log the radio id's displayed on the screen and create aliases.
@ProScan does logging and recording and is great for this task.