Where multiple pieces of equipment are involved you are definitely not tied to a single supplier.

All the equipment you require from any supplier can be financed under one master lease. If you need more equipment at a later date, then if your account has been kept in good order then it is a simple matter to add more to the master lease.

Alternatively, if you find that another leasing company is offering a better deal at the time the you could just agree a new finance arrangement with that lender.