Hello German,
You can create a CDB list and name it sysadmins with all the security group sysadmins members and then use the CDB List to trigger alerts, yes.
Let’s clarify that the CDB stands for Constant DataBase lists, so every time you make changes to the security groups, you will need to modify the CDB list and restart the manager/s to apply the change manually and your use case seams to be dynamic rather than constant.
The sync between the AD security group users and the CDB lists could be done with a script but you will need to restart the manager/s either way.
I’ve found that the dsquery command gives you the list of members of a group:
dsquery group -samid "Group_SAM_Account_Name" | dsget group -members -expand
dsquery group -name "Group Account Name" | dsget group -members -expand
If you do not make too many changes to the security groups, this could be practical.
Hope this helps!