There are practical considerations. Ideally one would put each chemical with only the same material in the correct sized secondary containment bin. The correct size secondary containment bin is whichever it the larger volume between A.) 100% of the volume of the largest container inside, or B.) 10% for the total volume contained.
Scientific Plastics makes Spill Trays — Secondary Containment for inside cabinets and on shelves.
Spill trays can be purchased through Scientific Suppliers via the PantherExpress System, just ask your vendor of Choice for a quotation.