Using one common voltage regulator and a network of LC filters works sufftiently and effectively ..
This network works even better if all segments of a circuit are fed directly from the regulator, then through LC ( or Cs of different capacitancies) filter and then to that segment ..
In some papers you will find a "serial" network of LC filters, but, in my oppinion, much better results as far as noise is concerned, you will get if you connect these LC filters in "star" configuration ..
And, as additional precaution, you should consider proper shielding/screening of all sensitive segments ..
Regards,
IanP