Absolute noob here, trying to design a serial countdown on four seven segment display

Okay, here's what I've got:

module binary1_to_led (
	// Create input from the clock.
	input  bin_counter,
	// Create output busses for the counters.
	output reg  counter_out); 
always @ *
	case (bin_counter)
		// output to Hex0
		3'b001 : counter_out = 7'b0000000;  //
		3'b010 : counter_out = 7'b0010000;  //
		3'b011 : counter_out = 7'b0011000;  //
		3'b100 : counter_out = 7'b0011100;  //
		3'b101 : counter_out = 7'b0011110;  //
		3'b110 : counter_out = 7'b1011110;  //
		3'b111 : counter_out = 7'b1111110;  //
		default : counter_out = 7'b1111111;
	endcase
endmodule// end of module counter

I have four of these (counter_out->counter_out4) broken out in for different .v files.

So, do I need to:

1) Put all of the counter's in to one file.

2) Create outputs for each counter_out

3) Create some kind of a function that basically says:

while not 3'b111

do

3'b001 : counter_out = 7'b0000000; //

3'b010 : counter_out = 7'b0010000; //

3'b011 : counter_out = 7'b0011000; //

3'b100 : counter_out = 7'b0011100; //

3'b101 : counter_out = 7'b0011110; //

3'b110 : counter_out = 7'b1011110; //

3'b111 : counter_out = 7'b1111110; //

done

default : counter_out = 7'b1111111;

while not 3'b111

do

3'b001 : counter_out2 = 7'b0000000; //

3'b010 : counter_out2 = 7'b0010000; //

3'b011 : counter_out2 = 7'b0011000; //

3'b100 : counter_out2 = 7'b0011100; //

3'b101 : counter_out2 = 7'b0011110; //

3'b110 : counter_out2 = 7'b1011110; //

3'b111 : counter_out2 = 7'b1111110; //

done

default : counter_out2 = 7'b1111111; (<-- I don't think I can specify multiple defaults)

etc, etc?

Thanks,

D