Need help with opportunity workflow

Hi,

We have a workflow that triggers whenever a new opportunity is created and sends it to the integration queue. We want to put a condition in the workflow that would only trigger if its a Parent Opportunity. None of the child or sub opportunities should be passed onto the integration queue.

I have hoping to put a condition based on Parent Opportunity ID or Parent opportunity name but I dont see those fields in the workflow.

Any help would be highly appreciated since its a little bit urgent.

Thanks

MUhammad