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.
Without the laws to enable it, the prosecutors would be unable to do that, and the only way to prevent prosecutors from doing that is to make laws that forbid it. The only way to change this while working within the system is through the legislators.
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.