Vizlib Line Chart - Conditional Data Driven Annotation

When using the data driven annotations currently, you cannot use an 'if statement' or anything in the dimension. If this was possible that would allow for a conditional selection of which annotations to place.

For example, I have a line chart where I would like to have an annotation for only the last day of the month. Currently, the only way to do this is having a completely separate table with only the annotations desired in it. The data team I work with does not wish to make a table for every set of annotations required, as this is a huge waste of space.