Adding items to the subtable

I have realy big pricelist (aprox. 65.000 items). When i'm creating order i have a subtable with reference field to this pricelist. When i'm adding new item to this order it's loading whole pricelist every time it's really slow. Is it posible to add items though some other empty field by entering a item number and function would search that item number in the pricelist and add all info from the pricelist to the order subtable