How to `rearrange` values only if they are in a certain group?
It looks like you want to arrange the data first by ourid, then by class (descending), then by compid, then by product (descending). We're using descending for class and product because your desired order seems to be reverse alphabetical. If you have more than 2 categories of product or class, you could do a custom order by converting them to factor class and specifying the order of the levels.
data %>% arrange(ourid, desc(class), compid, desc(product))