Can I do the equivalent of a shift register with a variable start value?

I have an array of samping frequency values (determined by an external signal) and I would like to extract one value at a time from this array to use as the sampling frequency for another signal.

The shift register almost does what I want. The problem is that I don't always want to start at element 0, but rather at the first positive sampling frequency value, which has a slightly different index each time. Once this value is reached, I want the index to increment by 1 each loop iteration (which it already does).

I have attached a VI for reference. Any suggestions?