Hi!

I need multisites with these specifics :

Single sign on
Sharing Cart
Non sharing products

it's possible?

With our "Single Sign-In for domain", you can have the single sign on.

Sharing the cart and not sharing the products depends on the extension that you are using to manage the ecommerce and how they process the shopping cart.

Some shopping cart use the session to store the information.
That mean that if you store the shopping cart in the session then it is mandatory that your different website domain or subdomain or subdirectory that would share the shopping cart also share the product info.
Otherwise, it will not be possible to check-out in a website that would make reference to product that does not exists.

Our SSI for domain result by sharing the session. Therefore you can have the same shopping cart session info but as explained your data must be consistent and probably require that you share the product.