Visit Local Car Renting Agency
You can start search for the van with the capacity of passengers you want to transport by visiting your local agencies. A visit in advance can help you find a right van at a right price. It is possible that if the agency does not have the vehicle, they can arrange one for you, if you allow them a substantial amount of time. It can be easily done if you need the vehicle for a day or two. Even if they do not rent the van themselves, they can arrange it for you from their connections with other rental garages.
You can also search online on the agencies' websites, check the van's specifications if they fit your requirement and book online. You can also inquire from them if they can arrange you a van fitting your requirement, but you will need to allow them some time.
Consider Your Budget
It is possible that you can find a van that fits the passenger requirements but is not within your budget. In that case you can either keep on looking for the van that can be rented with your budget allocation or you may need to revise your budget allocations to fit the rental agency's requirement. You can pass on the additional expense on the passengers if you are charging them for the rental cost.
You might be able to find a van that is within your budget limitations and all other features but does not fit the number of passengers you are planning to transport. In that case you might need to revise the number of passengers or else find a bigger van.
In renting of a full size van, you should consider the number of features you are expecting in the van. A music player or any other special requirement, especially if your passengers include a special person who has certain requirements. You should consider all features in advance and ask the rental agency to consider them while renting out the van.