API call to create/modify/delete an access group

[Fang]

Dear XNAT community,

I have gone through XNAT documentation try to find the API call to create an access group for a project, but couldn't find it. 

Creating a group from XNAT project page is fine, I can see in the server log that the client sends a POST request to /data/projects/{PROJECT_ID}/group. 

Could anyone shed some light on the API documentation that deals with groups? 

Many thanks,

Fang