LM317 Voltage Regulator multiple output where one is 12v constant and adjustable
There is no problem connecting two or more voltage regulators to a common source, so you could have one LM317 set up as a fixed 24 volt (for example) regulator, and another LM317 as an adjustable regulator both connected to your 36 volt source.

You must provide appropriate heat sinks to deal with the power dissipation in each regulator, and ensure that the total current drawn from the two regulators does not exceed the capabilities of the 36 volt source.