One is a frame and forks which I feel needs it's own post due to the in-depth nature of the post, which I wouldn't want people to have to wade through to find info on other items. I'm only listing 3 things so felt it easier for someone to see the proper item info in the thread title and not have to click on it if they're not interested to see what else is in the post but not the title. I prefer it that way when I'm browsing to buy.
If I was listing any more than 3 items then I'd group them. I didn't feel 3 threads was overdoing it. The max allowed at once is 5.