Traditionally the bride and groom both receive their rings during a formal engagement or in the case an engagement is not held, during the wedding ceremony. The point is that the rings are blessed then worn. Now days girls either receive their ring as part of a proposal or a xoskap, which is not truly traditional and has no religious meaning. As for blessing rings during a xoskap, I guess that would automatically turn the xoskap into an engagement as it will add the religious aspect. Xoskaps are traditionally a promise amongst the families, not between the couple and God. Hope that helps!
-Anasheh