You can just use files as a temporary buffer: (/my/bg_producer1 > /shm/file1) & (/my/bg_producer2 > /shm/file2) & /my/longrunningfgjob wait

You can just use files as a temporary buffer: (/my/bg_producer1 > /shm/file1) & (/my/bg_producer2 > /shm/file2) & /my/longrunningfgjob wait (/my/consumer1 < /shm/file1) & (/my/consumer2 < /shm/file2) & wait