Yes. Just select the "consolidate orders" option on the order form. My US partner will then repack your items and ship them as a single package. There is no additional cost for consolidation if this option is selected before the first order has been placed by my US partner beyond the standard minimum order fee.
If you wish to add a new order to an order that has already been placed by my US partner then you can, but there is an additional US$5 fee for doing this. This extra cost is on top of the minimum order fee. Orders can only be added to (late consolidated) before the first order has arrived at my US partners address (i.e. you can't add to an order once it has been packed up for shipping to you).
Please keep in mind that consolidating orders may cause your orders to take longer than shipping the items from each stores separately since my USA partners have to wait for all your items to arrive before they can ship. Due to the minimum order fee that it may also be cheaper to order all items from the one store than split your order over several stores.
As a general rule it does not make sense to consolidate orders if you have chosen economy shipping as it will not save you money and will only slow down you getting your order.