ranking multiple measures and return string

Hi all,

I have 4 different measures and I want to rank them based on the lowest value, however,there maybe occasions where there are multiple low values. Consider the data set below.

option 1, 500

option 2, 600

option 3, 500

option 4, 500

as you can see from the dataset above, option 1,3 & 4 have the lowest values, therefrore id like to return a string "1,3,4". But in instances where there one lowest value just return 1 string value.

Any suggestion will be greatly appreciated.

Thanks in advance