The process needs to meet the Equal Opportunity Clause requirements since it is a four day engagement (three days or less are exempted). I do not know what your company's "full recruiting process" is, but it is perfectly acceptable for different jobs or different circumstances to lead to different recruiting processes, so long as there is neither actual discrimination, nor the appearance (as the appearance may be defensible, but still lead to trouble with the OFCCP). So long as there is a sound business reason, the decision is made before candidates are recruited and there is no adverse impact, it is not likely to be a problem. Simply put, it is very likely that the process for temporary admin position is very different from recruiting a new CEO or other senior leadership, and that is absolutely reasonable. Please follow up if this does not provide enough clarification for you!