Change the color object by object

I have shape layer with repeater. I need that orange color will be appearing on only one rectangle, rectangle by reclange, smth like loading process is often shown (sorry for the poor explanation). 

I'm just stocked with idea how to simulate it.... maybe some expression like Trim Path with Start and End of Offset, but for colors... Or dublicate layer with one orange rectangle which will jump from one rectangle to another 

... it it's real at all...

Thanks for your tips in advace!