Custom List via VBA with a twist

[Momentman]

Working on a shift roster. I have 8 items like this A,A,B,B,C,C,C,C. I want to fill all the days of the month with this list, the challenge is that the 1st day of the month could be any of the 8 items.

i want the user to select either A, B or C and select the occurrence of it and the first day of the month becomes that and from there the whole days of the months are autofilled

Excel 2010

	A	B	C	D	E	F	G	H	I	J	K	L	M	N	O	P	Q	R	S	T	U	V	W	X	Y	Z	AA	AB	AC	AD	AE	AF	AG
1	Alphabet	instance	01-Jan-14	02-Jan-14	03-Jan-14	04-Jan-14	05-Jan-14	06-Jan-14	07-Jan-14	08-Jan-14	09-Jan-14	10-Jan-14	11-Jan-14	12-Jan-14	13-Jan-14	14-Jan-14	15-Jan-14	16-Jan-14	17-Jan-14	18-Jan-14	19-Jan-14	20-Jan-14	21-Jan-14	22-Jan-14	23-Jan-14	24-Jan-14	25-Jan-14	26-Jan-14	27-Jan-14	28-Jan-14	29-Jan-14	30-Jan-14	31-Jan-14
2	A	1	A	A	B	B	C	C	C	C	A	A	B	B	C	C	C	C	A	A	B	B	C	C	C	C	A	A	B	B	C	C	C
3	C	3	C	C	A	A	B	B	C	C	C	C	A	A	B	B	C	C	C	C	A	A	B	B	C	C	C	C	A	A	B	B	C

<colgroup><col style="width: 25pxpx"><col><col><col><col><col><col><col><col><col><col><col><col><col><col><col><col><col><col><col><col><col><col><col><col><col><col><col><col><col><col><col><col><col></colgroup><thead>
</thead><tbody>
</tbody>

Sheet5​

 

[Momentman]

I hope I explained well enough