Gathering everyone by yard from time to time (12)
I believe the answer is:
occasionally
'time to time' is the definition.
(I've seen this before)
'gathering everyone by yard' is the wordplay.
'gathering' becomes 'occasion' ().
'everyone' becomes 'all' (I've seen this before).
'by' means one lot of letters go next to another.
'yard' becomes 'y'.
'occasion'+'all'+'y'='OCCASIONALLY'
'from' acts as a link.
(Other definitions for occasionally that I've seen before include "From time to time" , "Sometimes" , "every now and then" , "At times" .)