Pipeline Requisitions Process Question

Summary:

Recruiting lead has a few questions on pipeline req process:

We post internally to employees, but often need pipeline REQs for external marketing. Why? We might have say - 15 Lab Analysts all in different departments - 100% the same Job Description. So we need to post internally 1 by 1 for all roles, but externally we only need 1. 

Here is the issue with that 

1. If it is posted internally - as I understand it - it cannot then be linked to a pipeline REQ for external marketing?
2. Often times we may have a REQ that was opened internally for a few weeks to see if we had someone in house before going to market