Default the ROLE based on account type

Hi experts,

        I have a requirement to default the ROLE field(drop down) based on account type like

Contact should be created with default role "Contact"

Prospectus should be created with Default BP Role “ Prospect” in  Individual account

Competitor should be created with competitor role "Competitor"

Corporate should be created with role as "corporate"

Please help me with this objects with possible solutions

Thanks in advance.