How to search for multiple attendees linked to single payer in CiviEvent
Soft credits, by definition, allow you to credit a contact for a donation made by someone, for example the person who inspired the actual donor to make a donation. Paying for something on behalf of someone else is not considered a soft credit. 

That said, the participant list that you access via the Participants hyperlink to the right-hand side of the event in question (e.g. under Events > Manage Events) is a simple search meant to show you how many attendees you have. If you want additional information such as who registered/paid for a given person, you would be better off using a report, however, there does not seem to be one that will fit your needs:

The built-in participant report (Reports > Event Reports > Event Participant Report) will show only the Registered by Participant ID (not the name) and does not have grouping or sort options for either Registered by or Organization.

The Extended Report extension, on the other hand, gets you pretty close with
Extended Report - Participants (Reports > Create Reports from Templates > Event Reports):



As you can see from the screenshot of the left-hand side of the report, Extended Report - Participants does offer the Registered by Participant Name and allows you to sort by the same, however (and this will be the same for any report you use) the person who submitted the registration will not have a value in the registered by field, so while you can group the additional participants together, the actual registrant will be listed in the "None" group. 

The Fee Amount (which corresponds to the Fee Level) will always be divided up according to the selections made for each participant - this is important when you need to know who ordered what regardless of who actually paid. Both reports offer you the option of the Net Amount field (Total Amount less any Transaction Fees) that would only be populated for the person who paid, but neither of the reports offer you the Total Amount field (which would not exclude any transaction fees - screenshot below shows the right-hand side of the report):



So, in short, there does not appear to be something out of the box or available through an extension that will suit your needs, but from a development standpoint it is a simple thing to add additional fields to a given report.  

Sorry not to be the bearer of better news,
Tamar