Perhaps the RS's could be used in a similar KO tournament to be run alongside the senior pairs on the same night, interspersed between the races... Similar to the 4's, when they had reserve races after every 4 heats but their points didn't count.
maybe 6 rider handicap races with start positions based on the senior teams points after every 3 races.
And the winning RS gains points to be added to the main points of the senior pair