Vendors vs Multiple Warehouses

I am looking for some guidance on which is the best approach.
I am currently planning on how to integrate a dropshipping agreement I have with one of my existing suppliers. This is going o be a  hybrid setup, i.e. I will have some of the stock here to fulfil ourselves and if we are out of stock of one of the products we stock then they will drop ship for us.

e.g. if we have a product of theirs and the stock qty is > 0 we will send ourselves. When this goes to zero then the order will be drop shipped by the supplier. When we get stock back in then it will automatically go back to being shipped by ourselves.

Does the vendor setup handle this situation? If not and I have to customise nopCommerce then would it be better to start with the vendor system or multiple warehouses where I have a warehouse specific to this suppler?

In the standard system the allocation of stock to orders from a Warehouse does not happen automatically. If there is stock at any warehouse then you can sell the product.
It is not until you ship the order in admin that you decide which warehouse it is shipped from.

Warehouses are not linked to vendors. You can link a product to a vendor and the product to a warehouse but I dont know if that will help you or if you need it given you can decide a particular warehouse is for a specific vendor

If needed I have a pluign that does a lot of extra Shipping functions including the linking of vendors to warehouses. See https://www.selectsystems.com.au/shipping-manager

Thanks for the update, I have been looking at the vendor and warehouse options and I don't think they provide very much useful functionality for my needs.