Foren / Cotonti / Extensions / Advice needed - plugin making approach

Hi;

I would like to re-model the way of displaying pages in one category, and I'd like to ask for advice.

I want to display first date, then a list of categories taken from extra fields of pages having this date in the <begin date> - <end date> range, and then pages from that date and category. 

I think that first I should (of course check for category code, then) hook into page.list.query and replace $sql_page_string with my own sql request(s), then maybe hook into page.list.tags and generate tags (together with nested list tags based on different sql request?). Do I get it right?

I just want to make Events in one list category, the calendar will be included (probably ported from Genoa plugin)

Added 1 days later:

Thanks for help >_>