separate fields for specific contacts

As a realtor, it's helpful to separate clients as buyers and sellers. I am hopeful that a certain contact type can be linked to specific custom fields. 

For example: 

- contact type: buyer 
- custom fields with that contact type: budget to spend on property, non-negotiables (ie. 3 bedrooms, good school district, etc) 

- contact type: seller 
- custom fields with that contact type: asking price for their home, preferred closing date for deal

Ultimately I want to be able to have separate fields available only for specific contacts.