At least Dolby Digital takes the scenario into account, applying dynamic range control on 5.1 downmixing. Be sure to set the DD decoder to RF mode (as opposed to line mode) to adapt the range for stereo.

With DTS there's no such feature that I know of. Depending on the setup, though, I guess one could always tweak the mix coefficients (privileging the center channel, where most of the voices should end up) and apply a DRC effect somewhere on the audio chain. TVs and receivers sometimes have this last bit built in and exposed as "night mode".