Copy all cells in column that contain data & paste to first empty row of another column.

Hi,

Basically what I'm trying to achieve is to create a macro that will copy data from multiple columns over to the next empty blank rows in another column. Here's an example:

A	B	C	D	E	F	G	H	I	J	K
a2	1
a1	1
			b2	1		c3	1		bc4	1

Any data in columns D:E, G:H, J:K would be copied over to the first empty cells in columns A:B.

Any ideas as to how I might get started would be very much appreciated, thanks in advance.