Under the U.S. sentencing guidelines (e.g. http://www.ussc.gov/Guidelines/2011_Guidelines/Manual_HTML/5... or state equivalents), this is already the case. Although you may be sentenced to "105 years" for multiple crimes, if they're related to the same activity, those sentences are usually served "concurrently." It's left to the judge's discretion.

Your complaint at this point should be with prosecutors that use the most draconian possible sentence to promote themselves and pressure defendants, and with a media that loves the shock value of numbers like "105 years" when such a sentence would almost certainly never happen.