Aha! Develop: Split an individual's work schedule between 2 teams for capacity planning

My goal is to split a person's time between 2 teams (50/50). I'd like to have a schedule per team, so that I can indicate the days (or % of their time) they'll work on each team. Currently there is one schedule per individual, which is shared by all the teams, so this is not possible.

As a note: I am also aware that their velocity for each sprint is calculated by team by multiplying their "availability" by their average velocity from the past 3 sprints. This functionality is super helpful for planning a sprint, but does not help me to plan changes to their split allocation, or to run through different scenarios (70/30, 60/40 etc).