sorting clever formula

[driller]

Dear All,

In column A, i have a very long list of filenames. I need to sort the
filenames in the following order.
First order is the file ext. will be *pdf*.
2nd Order is that the filename consist of 3 digit numbers such as
005,008,012,036...etc..
3rd order is another file ext *doc*
4th Order is that the filename consist of 3 digit numbers such as
005,008,012,036...etc..

So will it be possible to produce a sorted filenames something like
this...in Column K
filename-005-fd.pdf
file-008.pdf
name.012-lk.pdf
longfile . 036(n1).pdf

I have seen before in this forum sorting clever formula . Any help will be
appreciated.

thanks in advance