Jimk and son should be considering those too. Engelberg is bit over 2 hours from Bern. Caveat is that Swiss guides are expensive and you need to do that for the Big Five at Engelberg and from some far ranging itineraries at Gemsstock that ChrisC skied but I have not.
Yes. Swiss Guides are expensive and typically cost 700+ CHF per day. Partial days are possible, but generally cannot be booked too far in advance; obviously, guides want/need full days. However, guides will start accepting half-day offers about 24-72 hours in advance. I did a half-day private at Verbier - primarily for my own safety, but also to ski the Backside of Mt. Fort and explore couloirs.
Below are typical Guided Group Days for the major Swiss Freeride/Expert Mountains (i.e. how to ski the best of Switzerland cheaply and safely). These days are typically priced at 190 CHF per day.
I rationalize that I am paying the equivalent of a $300 Alterra/Vail ticket at Squaw/Snowbird/Jackson, but getting a much better deal --> a local guide to access the best terrain, untouched powder, and cutting lift lines at some places. Less crazy, manic Powder Panic. Europe can be a much, much better value at the Expert end of the scale.
Andermatt - Andermatt Guides. (Funny - this operation was created 20 years ago by an American, Dan Loutrel).
Every Friday, they organize "Freeride Fridays" from January to mid-March.
https://www.andermatt-guides.ch/service-page/freeride-friday-2
This culminates in a 4-day Weekend in early March of Freeride activities.
Additionally, they offer numerous 'courses' (guided skiing groups) throughout the winter.
https://www.andermatt-guides.ch/
Engelberg - Engelberg Mountain Guides
Every Saturday, they offer "Big 5" Tours from January to mid-March.
https://www.engelbergmountainguide.ch/winter/freeride/freeride-tag/
Or on other days, if a guide is interested:
https://www.engelbergmountainguide.ch/winter/freeride/die-big-5/
Powder Day Alarms - sometimes last-minute guided days.
https://www.engelbergmountainguide.ch/winter/freeride/powderalarm-engelberg/
Lots of courses
https://www.engelbergmountainguide.ch/en/calendar/calendar-2/
Verbier - Verbier Guides / Les Guides de Verbier
I am surprised Verbier does not have larger sources of Freeride Guided Groups, like Val d'Isère, Chamonix, and St. Anton.
However, every Wednesday they offer Freeride Groups from January to March.
https://guideverbier.com/en/activite-hiver/freeride-verbier-2/
Note: They do not actively promote these groups and typically go out with a minimum of 3-4 persons.
I have not researched Freeride Days at other Swiss mountains, such as St. Moritz (Corvatsch/Diavolezza/Lagalb), and Davos (Jakobshorn/Parsenn). Davos offers 'Yellow' controlled itineraries that extend beyond the backside to bus pickups, allowing for a DIY experience.
Zermatt and Zinal/Grimentz - I did not find groups. One possibility: Guides and Heli Zermatt will conduct single drops on high peaks and may organize groups. These outings can range from the Schwarztor to other prominent peaks.
I should consolidate all my Europe Guiding Info in one post. Add St. Anton/Arlberg, Chamonix, Courmayeur, La Grave, Val d'Isère/Tignes, Alpe d'Huez, and Serre Chevalier.