The answer here has 2 steps:
First step - you need the specific traffic to be matched on access policy rule. Here I agree with @Chris_Atkinson , IDA is the way to go here IMO but nothing specific is required except matching a rule.
Second step - enable alerts on the rule and define the alert.
1. Right click "Track" column on the specific rule -> Alert -> Choose alert type (See 1.png).
2. From main menu, go to Global Properties (See 2.png).
3. Navigate to Log and Alert -> Alerts. For each alert you can choose if you want to send alerts to SmartView Monitor, run script or both (See 3.png).
From here you can choose whatever method you see fit to your needs. If you want to define email alert you can use the following SK: https://support.checkpoint.com/results/sk/sk25941
Kind regards, Amir Senn