Talk about common cause with the other peripheral countries is coming basically from the left, economists and some, marginalized now, socialist politicians. The government is selling the line that says that this current crisis is first of all due to internal pathogenicities and "we are all to blame" thus we should "manage our own house" according to our debtors dictates, and never mind the others  - and on the other hand seems to pursue a n EU strategy of being an obedient poodle of Merkel's, thus hardly likely to participate in any sort of peripheral disgruntlement.
Perhaps behind the scenes there is some sort of communication with the other debtors, but it certainly isn't part of the rhetoric or the official policy of the Greek government.

Regarding the Swiss bank accounts, the government has gone on record saying that there is a lot of Greek money in Switzerland but not that much (perhaps 40 billion, they say). It seems likely that the 600 million might be some sort of total amount of transactions through Swiss banks. I would trust Spiegel (the alleged source of this information) over the Greek government on such matters however. The government has suggested that it might pursue a German-style deal with Switzerland regarding tax-evaders, perhaps by imposing a one-off 10% tax on any deposits by Greek citizens not declared to the tax authorities already (I reckon that 2-3 billion Euros of all Greek Swiss bank accounts are properly taxed in Greece). However it has also been rumoured that after the Swiss-German deal a lot of Greeks moved their deposits from Switzerland to other, ostensibly "safer" tax havens. So I'm not sure how large a part of this stash can be taxed. But any part would help.

As to how it got there: Political corruption, bribery, crime, shady bookkeeping and no effective watchdogs...  a lot of money changed hands in Greece over the last couple of decades, money that was not invested in the real economy, or money extracted from the demolition of the real economy

The road of excess leads to the palace of wisdom - William Blake