A similar thing to GPs pensions exists with former service personnel retiring with a pension and then taking up employment as FTRS or CS. They get their pension and then start to build up a second pension. There are penalties and so on before 55 but after 55 you get the full unabated pension.
However these are existing T&Cs so would need to be introduced in the future. So much of what both parites would do are cast far in to the future. Sometimes we forget and suddenly it all goes dark when the legislation kicks in.