First add the blocking user name to the alarm message details:
1. Open Alarms window from Configure toolbar
2. Choose the connection name
3. Edit Locks - Blocked Processes alarm
4. Disable Factory Settings option
5. On the High Severity threshold, edit the Description field and add this to the end of string:
Blocking User: {{SQLBlockingList.BlockingDBUser}}
Next, create Alarm Action rule that sends email for specific user account:
1. Open Alarm Actions from Configure toolbar
2. Click New and enter name of rule
3. Add 'The alarm is' condition and choose 'Locks - Blocked Processes',. Add 'The connection is' condition and choose connection name. Add 'The details contain' condition and click Add to enter the specific user account name. Click OK to close.
4. Add 'Send email to' action and enter email address
Generated email will have alarm details with the blocking user account and Spotlight will only generate email if alarm message contains the specific user account.