[galaxy-user] Default Display replicate libraries with different colors

Hi all, I have two small RNA libraries that are biological replicates. I mapped the reads onto the genome using Bowtie and displayed the BAM files as two individual tracks on the UCSC genome browser. However, this is not very nice. Ideally, I would like to color the reads from each library with a different color, so that I could display them in the SAME track. Because the two replicates are color labeled, I would be able to tell which experiment a particular read comes from. I have two BAM files from each library. All I need to do is to label them with different colors, then merge them before displaying on genome browser. Does anyone know how to do this? Thanks in advance for your help! -Eric