I am not sure that you need to add the "manufacturer" in the URL in the case when you have a 1-1 relationship between the subdomain name and the vendor.
The "vendor" or "manufacturer" name could be used as JMS slave Site ID.
As the Site ID is an information available everywhere in all the extension, you could use this "hidden" value to filter the product.
Another solution could be to add a "product type" in which you create a field "Site ID" where you will select for which website you want to display the product.
You also have the free "Search/Replace" plugin that add facility with JMS as you can use Site ID as a keyword.
www.jms2win.com/en/component/docman/doc_...rch--replace-utility
The "VM order" can not be excluded from the sharing in standard.
If you want that we create a specific rule to exclude the VM order, this is possible with our billable support. We just want to warn you that we can not guarantee you that exclude the "orders" form the sharing will not create inconsistencies in VM.
The order number and bill number are different things.
Do you use a specific extension to generate the Invoices based on the orders ?
JMS is not based on Synchronization that suppose duplicated data.
It is based on the sharing of a single information.
Therefore, if you want that the master see all the order then you need to share them.
If you want that a slave site see only its own orders, you need to modify VM to do that.
It seems that in your mind the Bill and the Order is identical.
Normally, this is not the case. An invoice should only be generated when the deliver corresponding to the order is performed.
In addition, the invoice should only take in account that item that are physically delivered.
In all cases, it seems that you need to modify VM to add filtering.