Organizational Chart - No way to view all Employees of all Companies

Is your feature request related to a problem? Please describe.

I'm working with the following Company structure. There is a group company and two child companies. Some employees of child companies report to employees of the group company. Some employees of one child company report to employees of a different child company. I can't view the whole organizational structure because I can choose only a single company in the Select element. When I select the group company I only see employees of the group Company and I don't see employees of the child Companies in the Organizational Chart. The Select field in question:

Describe the solution you'd like

The Employee Tree has an example of what could work as a solution - "All Companies" https://github.com/frappe/hrms/commit/f7de07a086c4b49aae60a452b307b34afe1da024 If there was a way of adding this option to the Select field of the Organizational Chart it would solve my issue, because it would allow me to view the whole Organizational Structure.

Code for the Select field of the Organization Chart: https://github.com/frappe/hrms/blob/b65f1504cee019588a077d28ea16585e1ee96b24/hrms/public/js/hierarchy_chart/hierarchy_chart_desktop.js#L74-L98

Describe the alternatives you've considered

I see two other alternatives:

1. Allow leaving the Select field empty to view all the Employees
2. When selecting a group Company the user would see the employees from child Companies too.
3. Ability to set multiple companies for an employee.

Additional context

Installed Apps: Frappe Framework: v15.1.0 ERPNext: v15.0.0 Frappe HR: v15.2.0