Since you are doing it as a DIY project, you can ignore any "compliance rules"
There is such a thing as an "add on RFID reader" for intruder alarms, but you have to check a few things / answer a question first.
1) Does the existing panel have the option to be set/unset via a key switch?
All a remote RFID reader will do is read the tag and tell change an output, you connect the output to the "key switch" input of the existing panel. (Some panels you can programme a circuit to be a key switch input.)
If your panel does not have a key switch input, you can not proceed.
Question, why do you wan't RFID tags?
You will probably have to change the existing panel and keypad just so you can "badge it" to set/unset the alarm, is it worth it?
Also some alarms when badged with a fob, will then ask via the keypad do you want to set the alarm. (Seems pointless)
Also most alarms will not let you turn off the alarm with a code, you have to use the fob (Most alarms you can switch this option off, but it is often a hidden feature)
The worst thing is, you go out, and you come back with no fob, yes, you have lost it, you can't turn the alarm off as it is waiting for the fob. You will have to wait until all the bells and whistles activate then your code may work.
The official suggestion is that you keep your fob on a different key ring, so if your keys get lost /found by a criminal they can open your front door but not turn the alarm off. I know of a few (and it is only a few) commercial premises where they were cleared out because the keys were lifted complete with fob. Not to mention fobs are not cheap
I would never have a fob if you paid me.
There are a lot of panel manufacturers out there that supply panels / keypads with built in RFID, but I have found that if you ask 10 people which alarm is best you will get almost 10 different answers as it depends on what the person you spoke to likes.