I'm looking to see if the capabilities exist to handle a specific type of rental. We offer rentals on a month-to-month basis, as well as offer annual rentals, and 4-month specials. Each of course has their own pricing, and some include free add-ons! Is there a way to handle rentals of this complexity? There are several other variables that can come into play that I won't get into here, but in essence I'm looking for a way--through Shopify--to offer rentals of different prices, timeframes (for billing), and options/requirements for the rental.