what is the best way to scrape multiple domains with scrapy?
I do sort of the same thing using the following XPath expressions:

'/html/head/title/text()' for the title
//p[string-length(text()) > 150]/text() for the post content.
I have around 10 odd sites that I wish to scrape from. A couple of them are wordpress blogs and they follow the same html structure, albeit with different classes. The others are either forums or blogs of other formats.
The information I like to scrape is common - the post content, the timestamp, the author, title and the comments.
My question is, do i have to create one separate spider for each domain? If not, how can I create a generic spider that allows me scrape by loading options from a configuration file or something similar?
I figured I could load the xpath expressions from a file which location can be loaded via command line but there seems to be some difficulties when scraping for some domain requires that I use regex select(expression_here).re(regex) while some do not.