No, you have to enter each vehicle separately.

Furthermore, you can't use the standard mileage rate method for any vehicle you don't own.  You have to use the actual expense method and can only deduct expenses you actually pay for (if you don't pay for insurance, repairs, etc. on a borrowed vehicle, you can't deduct it.)  Frankly, you probably don't have the required documentation.

This is copied from a similar answer I gave last week to someone else using a borrowed car.

You can't deduct any expenses you don't pay.  Since the standard mileage rate method includes depreciation, and you don't own the vehicle, you can't use the standard method.

You may be able to use the actual expense method.  You need to keep records including a trip log or diary that documents all your business trips (date, business purpose, # of miles);  you also need to know the total number of miles driven for the year for that vehicle so you can figure the percent of personal miles and the percent of work miles.  You need all the costs for the vehicle that you paid and the total costs for those items from the owners.  For example, if you buy gas when you drive it but don't pay for repairs or maintenance, then you need the total amount spent on gas by everyone who drives that vehicle.  Any costs you don't pay, you can't count.  At the end of the year you total everything up.  For example, if you and the other drivers and owners together have 12,000 personal miles and you have 3,000 business miles, that's 20% business, so you can take a deduction of 20% of the gas or other costs that you can prove with receipts (but only the costs you pay -- if the owner pays for oil changes and insurance, you can't include them in the calculation.)