Possibly posted from storehouses (6)
I believe the answer is:
depots
'storehouses' is the definition.
('depot' can be a synonym of 'storehouse')
'possibly posted' is the wordplay.
'possibly' indicates an anagram.
'posted' anagrammed gives 'DEPOTS'.
'from' acts as a link.
(Other definitions for depots that I've seen before include "Storage places" , "Stations where passengers or goods are unloaded" , "HQs" .)