Can we create custom roles in Vivo

[Santhosh Anand Ramia]

Can we create custom roles in Vivo. Currently, I see the following roles currently available, 

•  Site Admin
•  Curator
•  Editor
•  Self Editor

Can I create a role "ABC" for example and define what content and functionality the role "ABC" has access to? 

If it can be done, can you please show examples or reference code or point me to the direction where I can customize this? 

Thank you in advance.