UDF - Combining VLookups

I am trying to write a UDF function where I lookup if a value is on a range on different sheet. I would like to be able to write what I want the result to be in the function. I also hard coded that the function need 3 range and 3 results, but I know it is possible the make the number of component vary depending on what the user writes. I would like my function to do that.

Here is what I have written so far :

VB:
Function find_para2(var As String, rng As Range, result1 As String, rng2 As Range, result2 As String, rng3 As Range, result3 As String)
If WorksheetFunction.IsNA(WorksheetFunction.VLookup(var, rng.Address, 1, False)) = False Then
find_para = find_para & result1 & ", "

[Code] .....