To achieve this requires an ability to synchronise a recently launched satellite with a pre-existing formation, which we managed between UoSat-2 and UoSat-12.
The hardest aspect of this synchronisation is bringing the satellite into the same orbital plane as the rest of the formation. This can only be achieved at the two points around the satellite's orbit where the two orbital planes intersect. The optimal way to bring the orbital planes together is in a single impulsive burn at the time of intersection. Plane change manoeuvres, however, are very costly in propellant and for small satellites this is not feasible. A different strategy therefore needs to be employed in which several incremental changes in plane are made through a series of repeated plane crossings.
An opportunity arose with the launch of UoSat-12 to try an experiment of maintaining a set of encounters where the two satellites would pass the common nodal line of their orbital planes at approximately the same time. This would allow the gradual plane change of one satellite into the orbital planer of the other. The opportunity rose serendipitously as the semi-major axis of UoSat-12’s orbit was just a few kilometres higher than one of the original Surrey satellites UoSat-2.