Hi,

You can create a new security group and assign this user group to the corresponding button. Once the group is assigned to the button, the button will be visible only for the users in the specified group.

by adding groups="external_of_group" to the button directly or via inheritance will do the above.

If you don't need this and button has to be visible always and has to raise warning, you can add below code to the first part of the button.

if not self.env.user.has_group('group_external_id'):
    raise AccessError(_("Do not have access"))

Thanks & Regards

Walnut Software Solutions