Clearly, this is a no-loose position of Hamas. If the PA/Israel posturing is a fiasco, the PA is discredited and Hamas wins the hearts & minds. Otherwise, the PA needs to court Hamas to offer some incentives for the reconciliation. Likewise, to achieve its objective, the US needs to involve Hamas in the process - again, Hamas would need to look tough but leave the door open. And that is exactly what Hamas is doing. At the end, when Hamas and the PA get together, Iran might be disappointed for being dumped by Hamas.
from the article: Hamas: Peace talks with Israel are dividing the Palestinian people