Complicated listbox code required...

I would really appreciate it if you could take a look at the following and perhaps offer some advice...

I have data within a work sheet set out in the following way:

	A	B	C	D	E	F	G	H
1	Allocation Ref	UPI	AllocStatus	AllocType	TransType	AllocStartDate	PeriodDays	Notes
2	1AD	RENA1	Processing	Rental	Online	02/03/13	3	...
3	1AD	RENA2	Ready	Rental	Online	02/03/13	3	...
4	1AD	RETA3	Ready	Rental	Online	02/03/13	3	...
5	2CB	RENB3	Processing	Sale	Instore	06/07/13	2	...
6	2CB	RENA5	Ready	Sale	Instore	06/07/13	2	...
7	3FE	REN4D	Processing	Rental	Online	13/09/13	5	...
8	4BE	RET44	Ready	Sale	Instore	22/11/2013	5	...

I have a two listbox's, a textbox and a command button on a Userform, Listbox1 and Listbox2, textbox1 and commandbutton1.

I would like Listbox1 to populate itself with data from columns A, D, E, F and G of "Sheet1".

However, Listbox1 will need to sort Column A of the worksheet "AllocationRef", into one instance of each reference found. For example, using the above data listbox1 would look like this:

LISTBOX1

(Returns Column "A" data)	(Returns Column "D" data)	(Returns Column "E" data)	(Returns Column "F" data)	(Returns Column "G" data)
1AD	Rental	Online	02/03/13	3
2CB	Sale	Instore	06/07/13	2
3FE	Rental	Online	13/09/13	5
4BE	Sale	Instore	22/11/13	5

When a user selects a row of the listbox, e.g. "1AD", the textbox would show that there are 3 items associated with that reference. In the same way "2CB" would say there are 2 items associated etc.

When a user selects a row and then clicks the command button, I would like listbox2 to populate itself with the data in column B and C, relating to the selected ref ( i'll use "1AD" as the selected row in this example)...

LISTBOX2

(Returns Column "B" data)	(Returns Column "C" data)
RENA1	Processing
RENA2	Ready
RETA3	Ready

Hopefully that makes sense... Thanks in advance.