I don't think there is. Scripted fields allow you to have a script read field-values from a particular document. However, to achieve your end, you need to do a "sub-query" (for lack of better word), to read-out the value from another document.
Is there a way you can index the data differently?
E.g. when you index, instead of only indexing the CD-run field to every document, also index the corresponding CD-run 'StartPlaybackTime'?