Welcome to Bubble!
You can likely achieve what you’re looking to do by using the “:group by” function within your search results. (Thread on the feature here).
Within your app, for each of the individual conference events, have a field (let’s call it “start time”) that is a date value. Use this field for your group by function.
For the visual setup you’re looking for, you may need to nest a repeating group within the repeating group for displaying the results, where the nested repeating group applies a constraint to match the “start time’s” value of the current group by cell’s value.