Not sure I understand you correctly,
depending on what user type you select, do you insert a row into a specific table or do you have separate fields in your users table to store dealer and salesperson.?
if the former is the case, I would set up an insert behavior for each of the tables, and set up the trigger conditional to the value returned from the select list in the insert form, so that the specific trigger only fires when the appropriate value is chosen.
You did state however, state... "How do I on "Insert" tell the system, that if I selected dealer it should insert the id into the dealer field of users table
and if I select salespersion, it should insert the id into salesperson instead ?"
I am wondering, if this is the case, why do you have two separate fields ?
Sorry if I have misunderstood your objective.
If It helps, attach your database structure so I can take a look.
