  We implement a super-localization method in the time domain that allows the
observation of the external motion of soliton molecules in a fiber ring cavity
laser with unprecedented accuracy. In particular, we demonstrate the
synchronization of two oscillating soliton molecules separated by several
nanoseconds, with inter-molecules oscillations following the same pattern as
the intramolecular motion of the individual molecules. These experimental
findings indicate an interplay between the different interaction mechanisms
that coexist inside the laser cavity, despite their very different
characteristic ranges, timescales, strengths, and physical origins.
