However, your sentences are not good examples. Firstly, it just adds more ambiguity to have the subject "Employment" being the same word as the noun before the "which" - "employment". Secondly, what does it mean to analyse "Employment in May was supported by the service-providing employment"? It doesn't make sense. Do you mean "the employment-providing service"?
Here is a sentence which makes sense, and which exemplifies your point:
"Employment in May was boosted by the employment-providing service, which was an expected outcome."