Fr. Mawdsley of the Fatima Center has been doing excellent work tracing the history of the Jews through the Old Testament and explaining why they are a huge part of the attack on the Church since they initially refused Christ as the Messiah...
His work is essentially an echo of Bishop Williamson, who acknowledges the giftedness of the Jews, their opposition to Christ in the current times, and their eventual conversion (NOT now), after which we can expect to see some of the most incredible martyrs and servants of the Church in salvation history.
He has been strongly recommending to Traditional Catholics that they NOT kneel during the Good Friday prayers for the Jews.
He has some excellent suggestion as to how to go about this, including approaching the priest, possibly weeks in advance (like now Quinqugesima Sunday), and suggesting this. In addition, talking to your Trad friends about it, so that when you do it yourself you won't be alone.
I think the general rules about singularity do not apply in this case, since this is a pretty important principal at stake. In the pre-1955 Missal we see that the rubrics expressly omitted the genuflection because we do not want to join in or in any way give the appearance of mocking our Lord as the Jews did - through the Roman soldiers to whom they handed Him over - as when they knelt before Him, handed him a reed for a scepter, etc.
The prayers for the Jews have apparently been tampered with several times in modern times, each time lessening the impact.
This video, of several he has posted, does a good job explaining this and why it is important that we get right the public prayer of the Church for the conversion of the Jews.