Loop within a Loop

Is it possible to grab a few details of a post, when displaying another post, if I know the post_id?

I have the marketpress plug-in that makes products sellable by using custom post types. I want to be able to link a product (tickets) to a post (an event) so that it grabs the details of the product and displays it at the bottom – then customer clicks to go to the product page. I would do this using a drop down selection box in the create post page to select which tickets to use.

can you initiate another loop within a single post loop?