Copy all cells except blanks, keeping the same spacing.

Hi guys,

I've looked around the web and cant find a solution to my problem.
What I want is similar to copy and paste, except it doesn't copy over existing cells in the final range.

I'll provide an example:
the following cells are
A1 = stringA
A2 = empty
A3 = stringB

B1 = 4
B2 = B1*B3
B3 = 5

resulting in:
B1 = stringA
B2 = B1*B3
B3 = stringB


Ideally I would want this to work for any sized range (rangeA and range B always the same column and row dimensions however of any size), and copying from any part of the sheet to another.

Any help would be great,
Thanks.
Jimmy