Hi Gurudutthv
You can resolve this in the follow way:
To accomplish the correlation on accounts having a global user like "ca30137" is necessary that you initialize a CustomFieldXX with the global user number, I mean 30137.
Now that you have initialized this field you must use it as rule for Explore and Correlate/Correlation Attribute
CustomFieldXX.ActiveDirectory.AccountID:3,0 or what you are using
CustomFieldXX.ActiveDirectory.NT_AccountID:3,0
You must initialize the CustomFieldxx for all global users before apply the Explore/Correlate action.
On the rule we can define substring for attributes on the endpoint but not for the attribute of the globaluser, for that reason we need to use a different field. I think this should be an enhancement in the Explore and Correlate/Correlation Attribute Rules
I hope this help
Efren