CRMoD - Opportunity Product Revenue - Participant Full Name field/value access?

Hello,

Is there a way to reach out and query the Opportunity Product Revenue's 'Participant Full Name' (Pick-list read only) field through Web Services or CRMoD's Advanced Search filters on user interface

Requirement: Query all those Opportunities whose Opportunity Product Revenue's 'Participant Full Name' fields are null.

Any help would be appreciated.

Thanks,

Ahamed