House for 10 south of France walking distance to public transportation?

dsbrega2,
To find a large property or house for 10 people, I would go to gites-de-france to find sa place. We use them regularly and find them to be a well-run organization with excellent customer service. In 2023 we rented a fantastic place in the Dordogne for 7 of us. (Not doable there without a car, but just an example.)
But where in the south of France are you planning to be? The "south of France" is like saying you want to visit the American southwest, which includes, California, Arizona, New Mexico, Utah, Nevada, plus parts of Texas and Colorado. Are you thinking perhaps of the Riviera? That seems to be what most Americans consider to be the south of France. Provence is very large and includes many areas besides the Riviera. (It is over 12,000 square miles.) You will need to be more specific in your search for lodging of any sort.
I always like to suggest looking at a paper map of an area for the best overview and the best understanding of the scope of an area. Also, picture yourself on vacation. What are you doing? What does the background look like? Is the sea close by? Do you have a reference from a movie perhaps? (I love the Cary Grant and Grace Kelly drive along the Corniche near Monaco!) These can perhaps narrow down the locations that you appeal to you for your trip, and make it easier to settle on accomodations.
If you can be more specific you will find lodging easier to find.

Thank you. That all makes sense. We would like to be close to Nice, a house with a pool and walking distance to trains/buses if at all possible.

I just did a search on gites-de-france for a place on the Cote d'Azur for 10 people. I didn't know what dates to plug in, so I just picked dates in May. When are you going? Are there ten people all adults? How many nights? I couldn't find anything there that fit your parameters regarding transportation. (Our place was in the countryside, not far from towns, but we had two cars.)
Booking.com has some places. I just plugged in some dates in October, 6 nights, and there are some places listed with 5 or 6 bedrooms. They all run about $4000.00 for 6 nights in October, and they are in Nice (or Nice area). I didn't check out their distance from public transportation. Anyway, it looks like Booking.com is a good place for your search. (I have often used them and never had a complaint.) Do some searching on their site and opt for villas, apartments, or entire homes in property type. You will probably find something.

Best of luck!