Java streams forming a map issue

I am working on a framework where we are trying to convert our traditional loops to streams. My problem is I wrote two separate logics to get price and colors but I would like to merge both together so it will be presentable

Code to get the price values

List<Double> productPrices = product.getUpcs()
            .stream()
            .map(e -> e.getUpcDetails().getPrice().getRetail().getPriceValue())
            .distinct()
            .sorted(Comparator.reverseOrder())
            .collect(Collectors.toList());

Code to get the colors under prices

      product.getUpcs()
            .stream()
            .filter(e -> e.getUpcDetails().getPrice().getRetail().getPriceValue() == 74.5)
            .flatMap(e -> e.getUpcDetails().getAttributes().stream())
            .filter(e2 -> e2.getName().contentEquals("COLOR"))
            .forEach(e3 -> System.out.println(e3.getValues().get(0).get("value")));

I harcoded price in the above section to obtain the colors, instead, i would like to get that as input from the list of price values and get an output in

Map<Double,List<colors>
output Map<75.4, {blue,black,orange}> 

I tried merging these both without success, any help would be appriciated.