I have a transaction OrderPlace which takes list of supplier as input and creates an order.
transaction OrderPlace 
    {
        o String orderId
        --> Consumer consume
        o OrderDetails details
        --> Supplier[] supply
        --> Commodity com1
    }
The order is an asset having list of suppliers
asset Order identified by orderId {
    o String orderId
    o String orderName optional
    o OrderState state
    o OrderDetails details
    --> SupplyOrder[] OrderSupply
    --> Trader owner 
    --> Commodity com1
    --> Consumer consume
    --> Supplier[] supplier1
    o Rating rating optional
}
This order is created when OrderPlaced transaction is called and that should create relationship between the list of suppliers.
I was trying the code below for a single supplier
order.supplier = factory.newRelationship(namespace, 'Supplier', OrderPlaced.supplier.getIdentifier());