You'll have to try and write the necessary CSS for that or make your own template for CB Field Groups. Adding new templates is just a matter of adding a folder to the below location.
/components/com_comprofiler/plugin/user/plug_cbfieldgroups/templates
So for example the following could be a new template.
/components/com_comprofiler/plugin/user/plug_cbfieldgroups/templates/mytable
You then add what files you want to override from "default" template (or any of the others) and modify them as desired. Now you can select your template within your field group field.
In your case making a copy of the "table" template and modifying it to fit your needs is probably the easiest solution to have exactly the table structure you want. As for CSS solutions you can try things like the following.
Code:
.cbFieldGroupTable thead tr th:first-child {
display: none;
}