script to generate a string with all group selected channel name

Hello, I need to use the function "ChnStatisticsChannelCalc" like below:

Set ChnResult = ChnStatisticsChannelCalc("'[2]/MAIN_T_OUT_act','[3]/MAIN_T_OUT_act'",32,15,45,0,1,1,"NameName")

The script is to automatic get all the group channel name in string.

Attached is the code.

for i =0 to n-2

oChname(i) = "[" & str(i+2) &"]" &"/"& str(oChn)

next

Here has a error "subscript out of range".

Also I need the oChstr can contain all group selected channel name in string.

Please help me to check it.

Thanks a lot