can i write a function based on a "lookup" value in a closed workbook??

[Ahkle]

Attached is a file i want to use index and match function to look for the value ..and based on the lookup value, i would like to do some mathematics calculation on it in another spreadsheet, is it possible?

i know i can refer the value in a closed workbook like this for excel...=INDEX('P:\AC\[Trim3.xls]Sheet1'!$A$1:$C$6,MATCH(E1,'P:\AC\[Trim3.xls]Sheet1'!$A$1:$A$65536,FALSE),3)

But my intention is to build a function ...something like x=worksheet.function.index...and i can do some maths based on this x value