Separate volume level for speaker-phone mode?

My phone (a Samsung Vibrant, aka T-Mobile's variant of the Galaxy S) has a single volume level for both the speaker-phone and normal modes. I like to have it up high if I'm using speaker-phone mode and less deafening when I'm holding the handset to my ear. This causes some problems when I use a different mode from the previous call. Is there any way that I can have a separate volume level for the two modes of operation?