for some reason, the following enterred into custom format does not work

[=10000000]#,###\,##\,##\,##0;[=10000000]###\,##\,##\,##0;[=100000]##\,##\,##0;##,##0

whereas this works fine

[=10000000]###\,##\,##\,##0;[=100000]##\,##\,##0;##,##0

attempting to accomplish numbering format (format used in India)

Y,YYY,XX,000.0

in other words, at the US 'thousands' break (0 break to X), there is a comma
then the next break between X and Y (hundred more), with another comma (as
opposed to the next thousands break)
then it begins to count like U.S., every three digits

The XX is called 'lakh'
The Y is called "crore"

So what in U.S. would be 10 billion (10,000,000,000) would there be
100,000,00,000 (one hundred thousand crore). I am trying to accomplish this
with custom formatting, but either I'm enterring the wrong formula (note:the
formula for break between 'lakh' and 'crore' (X to Y) does work. It is the
longer one, which tries to force the regular reading of the 'crore' amount,
which says it cannot be understood.

Any help?

--
Boris