Bandwidth throttle per process

Hi

Is it possible to throttle the bandwidth on a per process base ?
I’ve been using Amazon S3 for backup ( quite happy with it ) and in order to avoid losing all my tiny upstream I’m currently using these tricks I’ve learned here:

sudo ipfw pipe 3 config mask dst-ip 0x000000ff bw 200Kbit/s
sudo ipfw add pipe 3 ip from any to any out

but whenever I have to copy files through a network it also hits this limit.

I guess I could:

– do the S3 thing on SSL and limit that port or
– throttle the upload only on port 80

But I feel I may fall in another trap again someday. What I really wanted was to limit the only the s3sync process’s bandwidth. Is it possible ?
Thanks in advance