We have pages which have been split into multiple pages as they are too in depth. The structure currently...
Page (www.domain.com/page)
We have split this up like so...
Page + Subtitle (www.new-domain.com/page-subtitle-1)
Page + Subtitle (www.new-domain.com/page-subtitle-2)
Page + Subtitle (www.new-domain.com/page-subtitle-3)
I need to know the correct way of adding in multiple canonical tags on the original page. Is it search engine friendly to add say 3/4 canonical tags linking to 3/4 separate pages?
Well, this is what you should do -
Keep the complete page even if you are dividing into component pages.
Use rel="next" and rel="prev" links to indicate the relationship between component URLs. This markup provides a strong hint to Google that you would like it to treat these pages as a logical sequence, thus consolidating their linking properties and usually sending searchers to the first page.
In each of the component pages, add a rel="canonical" link to the original (all content) page. This will tell google about the all content page.
This strategy is recommended by google - read here.