使用模式规则合并makefile中的相关文件

I'm using make to write a biological data analysis pipeline. I have a problem where I am unable to merge related files. For example, say I have four files (although the total number of files, and related files may be more): A_1.fastq A_2.fastq B_1.fastq B_2.fastq. When the pipeline is run in parallel I want each of the files to go through the recipes except the last, where I want related files to be merged e.g. A.merged.bam B.merged.bam. I am unsure how to write a rule like this in make?I'm using make to write a biological data analy