Use Business Logic Based On Attributes

Looking for some help please.
Is it possible to use WEB business logic to trigger events based on attribute selection?
For example I have a 'Change Request' an attribute called 'Change Type' which is a drop down menu with 'Mechanical', 'Electrical' and 'Software'
Based on which I select I would like the 'Approval Route' to be populated and an attachment created and linked to the change request.

Can someone tell me if this is possible? and perhaps offer some guidance on how to do it?

Thanks in advance