Hamaotome is a pretty big company, and I have found that they sell them at Japanese grocery stores quite often (especially if you are in a big city). To buy online, Tokyo Central is an online grocer and has theirs in stock sometimes!
Unfortunately Hiromedou is rather boutique, but you can use a package forwarding service to buy their seasonings. If you'd really like to order, email me at email@example.com and I can help you and walk you through the process 😊 But really, there are so many great varieties, if you stop by your local Asian grocery I am sure you can find something you enjoy.
I hope this was helpful!