I have a record in which the group "inventory/user" can read, create and delete a record in "calendar.event" object, but cannot write to it.

I'd like that this group can only write to the field "description" of that object.

When I try to write to that field I get the error:

The requested operation cannot be completed due to security restrictions. Please contact your system administrator.

(Document type: calendar.event, Operation: read)

How can I achieve this?