Jmeter : Loop through csv rows

I am using csv data set config, sample:

number, name, start, end

F002600_text_,value1,start limit(num1),end limit(num2)

F002601_text_,value2,start limit(num3),end limit(num4)

and wants to use soap xml requests for each row in .csv file starting from num1 and upto num2. I tried few combinations of beanshell preprocessor and loop controller to acheive the same but not working. Following is one such structure

Thread group

-- Foreach controller with values

      input variable : var1

      start index : ${start}

       end index : ${end}

       output variable : var2

        -- BeanShell preprocessor
        Here I am creating and assigning values to variables a, b
        a=value1
        b=F002600_text_ + loop count + start;

         -- SOAP/XML-RPC REQUEST
         a and b are being used in the xml request.

Please help.

Please note in each row lower limit and upper limit would be different and I need to use dynamic loop counter every time.