18 Wheeler is correct.
An amber ELEV FEEL light on the center instrument panel illuminates if their is a difference in system 2 or 3 pressure greater than 25% or if the feel system is powered by only one hydraulic system.
Their is no leak rate between the systems as these are all independent of each other.
The only way for one system can transfer to another is through the brake system.
Being systems 1, 4, and 2.
These has to be done manually.
A technic that maint uses sometimes on the ground to transfer fluid between the reservoirs.