At many physics departments a significant fraction of teaching is in support of engineers and scientists in other majors. These service courses are thus an automatic crucible of interdisciplinary interaction, and at times, strife. For example, the traditional algebra-based physics course is often considered by both biology faculty and students as having little relevance to their discipline. To address this issue, our multi-disciplinary multi-university team has been negotiating the role of a physics in the curriculum of life-science students; In NEXUS/Physics we have designed a class that stresses traditional physics skills but in contexts chosen to better meet the needs of life science students. Non-standard topics include chemical energy, diffusion and random motion, and thermodynamics with careful discussions of entropy, enthalpy, and Gibbs free energy. Explorations into how physics intertwines with an engineer's curriculum suggests places where analogous negotiations could lead to substantial modifications of physics courses for engineers that substantially enhance their value for engineering students.