If you speak with the PA unity government you are dealing with Hamas. If you talk to Abbas you are talking to Hamas. If you talk to Lieberman you are talking to the Olmert and the ruling government. If you talk to Peretz you are speaking with the entire representative government of the state of Israel. If you meet with a member of the unity government, Fayyad for example, you are talking to Hamas. Not talking with Hamas is code for "no negotitiations", and "the economic embargo will continue." Negotiations will begin after years of formaldehyde (per Sharon) or when the Palestinians become Finns. Speaking with a unity government that represents 90%+ of the Palestinian people is exactly the group with which you wish to negotiate. The Palestinians must wonder whom there is to deal within the Israeli government. In the past 15 years there have been 8-10 PMs and new one coming soon.
from the article: Israel to snub foreign envoys who meet with Hamas ministers