Multiple Dropdown Lists in one cell

Hi Guys,

I am trying to create a formula to allow for multiple drop down boxes in one cell based on the information in another cell.
For example: If Cell B3 shows "(FL)" then I want a dropdown box list in cell C3 to show only items relating to (FL) which is "Flooring". Or if cell B3 shows "(WA)" then I want a dropdown box list in cell C3 to show only items relating to (WA) which is "Walls". and then if there is nothing in cell B3 I want C3 to be blank.

Cell 3B is already a formal/calculated cell based on a dropdown list in cell A3.

I was trying to use the below formula however within the data validation source imput, it doesn't allow for such long of a formula.

=IF(B3="(FL)","Accessories,Linings,Tiles", ? ?, IF(B3="(J)","Accessories,Benchtops,Cabinetry,Fabrics,Hardware,Tiles", ? ?, IF(B3="(FI)","Artwork,Handrails,Lighting,Signage", ? ?, IF(B3="(WA)","Bricks,Linings,Paints,Tiles", ? ?, IF(B3="(FU)","Decoration,Fabrics,Large Pieces,Rugs", ? ?, IF(B3="(H)","Door Handles,Sanitarywear", ? ?, IF(B3="(WI)","Films,Frames,Glazing,Treatments", ? ?, IF(B3="(DO)","Films,Frames,Glazing", ? ?, IF(B3="(C)","Linings,Paints,Tiles", ""))))))))))