search and replace

Hi:

I have a pattern like this

"1,885,5002,666,59026."

and i want to separate out as
"1,885,500"  "2,666,590" and "26."

basically it should split the 3 groups depending on
the property a comma can split a max of 3 chars.

right now I am searching for [0-9]\{4,9} which
highlights the 5002 and 59026 in the above example.

Can somebody please enlighten me how I can split it
into those 3 groups?

This above pattern is part of this string

A 26.37 1,885,5002,666,59026.1326.00 - 26.79
which is a stock price for the day.

Thanks