Hi,
One approach i can think of is to first list the process ids
1. ps -eaf | tr -s " " | cut -f 1 -d " " > mytemppid.txt
2. sed '1d' mytemppid.txt > mypid.txt //Deleting first line teh header

Now for each process id see what files it has opened using
4. /usr/proc/bin/pfiles <pid>
Where pid is the process-id of the process.
It lists the inode numbers of all the files, opened
by that process.

Since its list inode number you need to know the inode number fo your file .
ls -li gives inode number for your file.

Hope this helps.
Regs,
Reddy