It was determined with CA Support Issue#22013049 that this is an ENH.
We need a way to change the lookup for an attribute from the default value to a user specified one when a SQL Query is used with grLoader, e.g:
grloader -cfg grloader.cfg -s http://someserver:8080 -a -n -E -u ServiceDesk
-p Password* -dbstmt "select osname as class, ServerName name, ServerName
system_name, ShortDescription description, FacilityName location, Memory
phys_mem, TotalDiskSpace hard_drive_capacity, NumberCPUs number_proc_inst,
CPUSpeed proc_speed, LeaseExpirationDate lease_termination_date, userid
resource_contact, userid billing_contact_uuid,Serverid asset_num,
ServerOwnerGroupName support_contact1_uuid, DomainName zDNS_Name,
SerialNumber zSerial_Number, Model zModel from Stars_New" -e
By default the lookup for resource_contact is combo_name and there is means by which we can change it anything else say for example userid using a SQL Query with -dbstmt switch.
07:06:21.668 CI and Relationship Loader for CA Service Desk Manager R12.9.000
GRLoader was built on Mon Oct 20 10:55:00 CDT 2014
07:06:21.720 GRLoader ended