Unit flow - combine processes for different PN for unique unit

I am looking for functionality in Unit flow to combine flow for the unit from different Part numbers flow. 

We have situation that our units change part number during process and we have several test processes for different PN but it's the same unique unit. For example have have different PN for PCB level then different for first functional test, second functional test and for final configuration we have again different part number. And now I see different flows in unit flow for each part number. I would like to see it in one combined flow. 

I have asked Alvea about this but received answer that this feature seems not be possible now. And is working like that because in WATS PN+SN creates unique unit not only SN.

Is it possible to implement such solution? it will help us a lot with analysis and I believe that changing PN during process is not only done at our company :)

Kind Regards,

Dawid Oberda, Scanreco