Generating notification based on more than one parameter

Hello,

I receive an event from a device in the following example format, "event=a,b,c,d ". where "a" is the type of event and b,c and d are  parameters of the event.  what I need is to check  the occurrence of event a and the occurrence of this event in a specific geofence and if true  display event parameter b in  notification text. Please advise on the possible way of achieving this.

Thanks !