I created a new group with the help of XML.
<record id="group_custom_manager" model="res.groups">
<field name="name">Custom Manager</field>
<field name="category_id" ref="base.module_category_hidden"/>
<field name="users" eval="[(4, ref('base.user_root'))]"/>
</record>
but in my case, after creating this group. I have to manually enable the group for other users.
Is it possible to enable this group for all users automatically??