Page 9 of the Frequently Asked Question:
https://www.games-workshop.com/MEDIA_CustomProductCatalog/m3440036a_40K_RULEBOOK_v1.5_September_13.pdf Q: Can you deploy the Aegis Defense Line sections in two
or more groups of two or more sections apiece (this way
they would still be in base contact with at least one other
section)? ([114)
A: No - The Agis Defense Line sections must be deployed
in an
unbroken chain, though they can be connected
end to end such as in the example shown on page 114.