If you mean Views tab in group, You can restrict a view to be shown only by current group only so other groups will not able to see this view and you can do that by code as below as an example: 

In the below view, we restrict view  email_compose_message_wizard_form to be shown only for Employee/Employee group

<record model="ir.ui.view" id="email_compose_message_wizard_form">
    <field name="name">mail.compose.message.form</field>
    <field name="model">mail.compose.message</field>
    <field name="groups_id" eval="[(4,ref('base.group_user'))]"/>
    <field name="arch" type="xml">

You can do that from groups using Views tab but you have to know that each user may belong to a several groups and a group can inherit all the rights from another groups and that's what you encountered.

You have first read about security on Odoo before applying anything into the system and the below link is useful for you:

https://www.serpentcs.com/serpentcs-security-in-odoo-users-groups-access-rights-record-rules-230