How to protect 61000-4-5 surges to earth and conform to isolation

Hi,
I have a problem with the 2kV line to Gnd passing though my power supply and disrupting the operation of a surgical generator.
The surge seems relatively easy to supress with varistors, or a combination of them with a gas tube. However there is, I think, a requirement with withstand an electrical stress test of kV from the Lines to earth. The protection will obviously conduct and the test will fail. This is a Class I device with an earth terminal.
Is there any way around this dilemma?

Thanks for any replies on this,

The question is not clear to me. Could you pls provide a block diagram ...?