One common option is to set the form up to also submit to the library it is published to. You can promote fields as columns in the list. When the user submits the XML created by the form, the columns are populated with data from that XML. You can use a formula or form field for the form name to help ensure uniqueness, so that submitted XML don't unintentionally overwrite each other. You can then leverage the data promoted into the library columns for grouping, views, etc. Many people can use the form at the same time by clicking New Document in the form library.
Hope that helps!