Minimum Purchase Error

Product:Quantity:Price:Total:FE-190 Caterpillar 3208 425/435 hp Single Turbo, Size 7 1/2" Base Diameter x 10" Tall Cone1$13.50$13.50FE-MTU-12V2000, size - 12″ Diameter x 15 1/2″ Tall Strait1$15.00$15.00FE-MTU-8v2000, size - 9 1/4" Diameter x 15" Tall Strait1$14.00$14.00FE-MTU 12V4000- 12V 4000 M60R, size - 16″ Diameter x 13 1/2" Tall Strait1$16.00$16.00FE-QSM11-M CUMMINS QSM11 Ever Quiet Oval Shaped Filters 8 3/4 DIAMETER X 11" TALL STRAIT CYLINDER SHAPE1$13.50$13.50 (5) Error  Error => Minimum Purchase quantity of 6 units required for this group. (Rule ID = 541)