Increased Trellis Functionality

Currently, splitting a visualization using trellises according to column names will split every column into separate trellises. There are many instances where it would be useful to plot several columns onto one trellis while plotting other columns on separate trellises. For example, I am unable to plot several variables along with their targets using one visualization with trellis rows (one trellis row for each variable and its respective target). It seems there is no way to accomplish this, but it is really something quite basic that should be included in the software. I can think of two methods to accomplish this - either allow some sort of interaction with the y-axis names so you could use an if statement to assign a group to each series in a custom expression for the trellis, or create a UI that can assign each series to a specific trellis.

Edit:

I have attached a basic example below. Let's say I have a list of injection wells. I have a daily data table that contains columns for the following for each well: daily injection rate, daily pressure, target injection rate, and maximum allowable injection pressure. I would like to create a line chart showing this daily data with trellis pages for each well in order to monitor the injection rate versus the target and the injection pressure versus the maximum allowable pressure. Each trellis page would have two row trellises - one with the injection rate and target injection rate plotted together, the other with the injection pressure and maximum allowable injection pressure plotted together. Currently I have to do this as two separate visualizations, as shown in the attachment, since I do not believe there is a way to do this as a single visualization using trellises. The issue with this is that the scrolling is not linked between the two visualizations, so if people aren't paying attention they may be viewing injection data from one well and pressure data from another well.