it has urls like:
is that correct?
By default ZAP build up its model of an application using the 'standard' url pattern, ie the structure is denoted by slashes.
So in the first case we have 3 pages (page1, page2 and page3) but in the second case we just have one (home) with 3 different parameter values.
However you can configure ZAP to understand that the 'page' parameter is part of the application structure by:
You should then see that the Sites tree changes from something like:
To something more like: