I am not quite sure what the last poster meant by "bridging" the two reservations. I work at the Front Desk of a Disney resort and there is nothing we can do that is called "bridging." If you have two more more reservations with different rates, those reservations can (and almost always are) be linked as continuing ressies. That means that you are pre-blocked for the same room for your entire stay. The room assigners have normally noticed your continuing reservations before you arrive and have pre-blocked you. But you can always check at the time of check in and verify that the room assigner has noticed and that you are pre-blocked for your entire stay.
But you are going to have to go to the Front Desk on the day your new reservation starts. The cashier will have to check you out of one reservation and into the next one. New keys will have to be cut for your room. It is not possible to cut one set of keys that will work for two or more different reservations. The computer system is also not designed to charge more than one rate during a stay. ......
In a Disney resort, you pay the room and tax for the entire stay up front (when you check in or prior to that). Then each night, the computer charges one night's room and tax from the total you have already paid. By your last ngiht in the resort, the credit
of what you pre=paid is used up by the nightly charges. But if the computer cannot charge different amounts on different nights.
Is there a software package that could do that? Perhaps. New systems are developed every day. But the system that Disney uses will not charge different amounts on different days. And I have previously worked for two other large chain hotels and the software there would not charge different amounts during the same stay.
IMHO, the guest is the one who decided to have two or more reservations. Therefore, I don't think it is that much of a hassel to just come to the desk, sign a new registration card, and pick up new keys.