I have a Graylog NXLog configuration that contains a multiline input. I'm trying to figure out what the best regex would be for the HeaderLine to delimit each message as a group for each instance of a username that appears in the log.

This is the desired output:

Message 1 should contain: Username : <Username1> Index : <Index> Assigned IP : <IP1> Public IP : <IP2> Group Policy : <GroupPolicy> Login Time : 15:15:34 UTC Fri Nov 1 2019

Message 2 should contain: Username : <Username2> Index : <Index> Assigned IP : <IP1> Public IP : <IP2> Group Policy : <GroupPolicy> Login Time : 15:16:12 UTC Fri Nov 1 2019

Instead, this is what happens:

Message 1: Username Message 2: Index Message 3: Assigned IP Message 4: Public IP

So on and so forth. Looking for advice on what should be put in the HeaderLine so the logs are delimited and can be read properly. Thanks in advance!