the default behavior is to allow all pdf pages scrolling when zoomed, also with paging enabled.
when you zoom out to minimum zoom level, the paging is enabled.
If you want to block the page change when a page is zoomed (with paging enabled), you should take a look at this
Knowledge Base article
I think you are trying to replicate the view pager mode of the Android demo project.
The view pager is a particular implementation for the Android version that manage each page separately but is not available on iOS version.
I think you can replicate something similar by setting the page zoom level to 1 when you change the page (onPageChange method), but the result could not be smooth as the Android version.
demo project contains a pagination implementation based on scrollView (pagingEnabled).
You can enable the scrollView paging by setting g_paging_enabled flag to true at the end of APP_Init method, in PDFVGlobal class.