Multiple Income Sequences Within a Single Subproject

I often need to schedule billing across non-contiguous periods within a single subproject - for example, a deposit upfront, a gap, then a final payment at completion. Currently I have to fill the gap with zeroes, which works but feels like a hack and makes forecasts harder to read.

I'd like to be able to define multiple discrete income sequences within a single subproject, each with its own start date, end date, and value, so that gaps are true gaps rather than zero-filled placeholders.