[galaxy-user] how to sort mapped data?

Hi everyone, I am working on RNA-seq data. First, I mapped the reads to the reference transcriptome using bowtie. I found some different reads mapped to the same gene with different positions. Before running Cufflinks, I would like to combine the reads that mapped to the same gene though with different positions. Is there a tool in Galaxy can fulfill this purpose? Any suggestion would be much appreciated. Thanks! Yan