Dividing a letters and numbers string

Hello,

Recently I've stumbled upon a small problem, which I just cannot overcome.

A given string of some letters (from three to five, six) is followed by a single number (1-4). Then it ends, or is followed by another such combination, up to a maximum of, let's say, four.

Example:
xxxx1
yyy3yyyy1
xyzxx1yxz4xzx1
xxx2xxx2xxx2xxx2

What I would like to do is to divide a given chain of characters into the smallest chains which contain only letters and one number. To the examples given above, I'd like to receive the following sets:
xxxx1
yyy3 and yyyy1
xyzxx1 and yxz4 and xzx1
... and so on

Is it somehow possible to do it with simple functions? Or is VB necessary (which sadly I don't know)?

Thanks,
Konkursor