Users product proposal

Hi. Sorry for my English. I am planning to create a website for a shopper. This shopper wants sell elements to collectors. These collectors are seen as users. They have already objects to sell. So the scenary is: only one shopper; multiple users that propose object to him. After the shopper validation, this object will be sold in the website for all the world. I repeat in other words: users in this site should be able to insert products with their price; the shopper take these objects and sell them in the website. If the objects proposed by users will be not checked, the objects will not be sold. Is this possible with Hikashop?