Copying cells with varied address reference

[Paragons]

I have data in rows A1:A100 and then again in rows A501:A600.

In cell A1001 I want to retrieve A1
In cell A1002 I want to retrieve A501
In cell A1003 I want to retrieve A2
In cell A1004 I want to retrieve A502
In cell A1005 I want to retrieve A3
In cell A1006 I want to retrieve A503

I want to be able to either select these files and copy all the way down to get to A100 and A600 data.

When I tried the fill handle I get A1, A501, but then A3 because I guess the two rows Im copying is incremented by two instead of 1.

I've tried some OFFSET formulas to no avail.

Macro, formulas?

Thanks in advance, Pete

[JBeaucaire]

In A1000, put this formula: =INDEX($A$1:$A$100, ROWS($A$1:$A1)/2+0.5)

In A1001, put this formula: =INDEX($A$501:$A$600, ROWS($A$1:$A1)/2+0.5)

Now highlight and copy the pair down at the same time.

[Paragons]

Worked, thanks. At one time I thought of looking up index

Pete

[JHONEDE005]

thank you for your solution.