creating purchase order for sales order

Hi,

We are distribution company and we takes order from customer and create sales order in order management and then send to partner company for manufacturing product.

Now I have to create purchase order for all the sales order for example received every hour for all the sales order  and then create a custom xml file to the partner.

Is there any built-in flow available for this kind of requirement or I have to built all  using interfaces?

thanks,

7Z