Create a live load reduction factor in the design parameters for each material type. This way the live load is captured in the analysis and reduced accordingly in the design. This might cause an issue with 2nd order analysis if you don't want all the live load applied, but that could potentially be handled separately.

Just make sure it's clear that 1 means you are using all the live load and 0.7 means 70 percent of the live load is being used. As opposed to 0.7 means that you're reducing the live load by 70% (30% remaining).

I don't typically need this, but I'm hoping it somewhat of a straightforward addition to the program.
Thanks!