DESIGN Question: How to set up a large catalog

I have a site that has few dozen products arranged in brands, then models, and then the item itself. I set those up in pages and page hierarchy, so that it looks like this in pages:
– BRAND
– – Model
– – – One product

Now, each product also needs to have 4 separate pages: Main blurb+photo of that item, a “technical data” page, a “gallery” page, and a “visual tour” page — this last item is an external link at another site.

I’m puzzled how to set up these 4 pages. I wrote some crude HTML with a table that shows up on the left site and manually inserted links to those four pages of that item. So, people see the links on the page, click and another of those 4 pages load up for that product. This works, but it’s tedious that I have to maintain this HTML for each product manually. I was wondering if there is a better alternative that I am not thinking of..

Many thanks, -t