Media Elements usage based on some index value that matches with media element name from code behind

Question

Hi,
 
       I am developing one application in that I have more than 20 media elements.Here is the example for 5 media elements mp1,mp2,mp3,mp4,mp5.
And i am using i value from 1 to 20 based on the i value i have to use that corresponding media element.If i value is 2 i have to use mp2 and assign path to that mp2 source from code behind.
Those all media elements are created by default through design.Please can anybody help me how to resolve this problem or any suggestions to achieve this task.
Thanks in Advance
Pavani