I'm not sure if this helps but i found this on the unimelb website for harvard style.
Hassan (2004) has argued that ...
OR
... as found in a major study (Hassan 2004).
If the sentences link with each other - you might be able to start or end like this.
You absolutely can - that is generally far preferred to referencing every single item when it's clear from the context they are all part of the discussion of the one text.
The best test is the one of common sense: a) Would a stranger coming to my essay know exactly which parts are mine and which parts aren't? b) For the parts that aren't mine, would they then know whose they are and where they come from?
Also, if you download EndNote (either install the full version from the library or download the free web 'trial' version) you can put all your sources in there and when you insert references into your Word doc it automatically formats them according to whichever style you use (and you can adjust the details for tutor preferences).