This is not an SvS tactic. It is a voluntary domestic arrangement after several alliances have agreed on the final Castle winner. Alliances rotate captures before anyone reaches the continuous occupation condition, preserving scoring time for rally leads and joiners.
Track the holder, current occupation start, continuous time, total time for every alliance, and the next landing. Finish either by keeping the agreed alliance first in total occupation or by reserving enough final time for it to complete the continuous condition. Exact timers and points come from the current event screen.