Please show us the structure of your file and what exactly you want to isolate.
I cannot show the original file but here is the example which will give the idea:
In the above picture it is shown that there are 4 layers. Each layer has different shape. Now I want to select the top two layers and applied isolated mode. But when I select the top two layers and go to the control panel:isolated mode the enter isolated panel is greyed out. Below is the link for clarification.
It does not appear to be possible to isolate simultaneously objects on separate layers. The concept sounds somewhat self-contradictory to me. What is your intent?
The project I am currently working on has 15 layers and each layers consist of different set of shapes. Now assume I want to work on layer 5,6 and not any other layer currently. If I am able to isolated by selecting layer 5 and 6 objects instead of selecting remaining layers manually then locking them out it will be much convenient and time saving workflow.
Alt-click next to the layer to lock all other layers.
By clicking Alt+left click to layer it is selecting all the objects of the particular layer it is not locking other layers.
The Haziq5DD6 and thromborator recommendations speak of a correct procedure.
A function that works inside objects with isolate mode groups. Isolating between layers requires a different process. You need to select layers and objects that you do not want to select, to be changed in any way, and DO NOT LOCK or HIDE them. This process is an isolation.
Alt (opt) - click one of the layers you want to remain editable in the lock-unlock column just to the right of the visibility (eye) column, then release Alt and click the lock of any other layer(s) you want.