Back in the day with dimensional lumber joists, it was common to box out an area for something like a tub drain that could not be moved due to floor plan layout. I remember seeing 2x8 or 2x10's doubled up on each side that a joist-box was needed. Then normally the floor joist designated for running where the drain box was made would stop short and hang on a perpendicular short joist spanning to both sides of the doubled joists.
However, what is the most economical way to do that with today's modern I-Joists? It would be rather expensive to run double I-Joists on each side, and it would seem hard to fit something like an LVL block in place between two joists because there is not an engineered LVL hanger I can find and I don't think the two side I-Joists would be rated to carry that end load especially if it's something like a tub full of water on this span.