When you want to do the right thing by your profession, chances are you you will not be able to help a vast majority of applicants.
To say that a migration agent selects a client based on the job title is an over-generalisation. An assessment needs to be made on the applicant’s work experience, qualification and even the English language competency as demonstrated in their email correspondence. Moreover, if their occupation is listed in the STSOL, then you would need to consider state nomination options available, if any.
In terms of job title, an ‘electrical engineer’ can actually be a technician, an administrative support person a Database Administrator, Property Manager, Program or Project Administrator, etc - all depending on the job scope and industry of employment. A ‘designer’ can be an Interior Designer or Graphic Designer, etc, an ‘Architect’ an Architectural Draftsperson, and so on.
The initial assessment (which is not a simple 'tick and flick process' btw) considers all possibilities and acceptance of a client cannot be based merely on the applicant’s job title.