That might somewhat work, but only for static conditions. A static condition means it won't dynamically show/hide during registration or profile edit, but will still apply on display. You can actually substitute in field group fields using the format shown in the below topic.
www.joomlapolis.com/forum/153-professional-member-support/242183-accessing-the-individual-fields-within-a-field-group#316989
So for example you might have the below.
[cb_fieldgroup__0__cb_checkbox]
This would get the value of the field cb_checkbox from the field group cb_fieldgroup of the first row. In your static condition you'd have something like the following.
Field: Custom > Value
Custom Value: [cb_fieldgroup__0__cb_checkbox]
Operator: Equal To
Value: 1
krileon
