I have noticed that sometimes, groups are defined as 

<record id="base.group_website_publisher" model="res.groups">
            <field name="name">Display Editor Bar on Website</field>
            <field name="category_id" ref="base.module_category_website"/>
        </record>

This is in the website module, and group_website_publisher has not been defined in base but it is stil defined as "base." 

Is that a correct practice? I have a global group, which I would like to use in several places. Currently, I have to use that module as a dependency everywhere, but if I could define it as base, it would help.