Multiple results to display based on selection made from drop down list

Hi there, I need some help in putting together a spread sheet where if one main item is chosen from the drop down list, then corresponding values appear in separate cells. I have attached a small example (jpeg) to illustrate what I am trying to do.

Basically my goal is have a dropdown list for items P1, P2 etc. In other words, that’s the item I want to select. So if I select P1, I want to see (in a separate column) that it belongs to D1, D3 and D6. In a separate column, I also want to see that P1 relates to S1 and S3 and that S1 relates to C1, C3 and C9 and S3 related to nothings.

I would be really grateful if there is anyone who can offer some advice or guidance on this.
Kind Regards
Annie