How to restrict the project no and task no values visibility under the expense UI

I would like to check how to restrict the INP project as below not visible under the project number and task number field drop down list in the expense template when create expense report? 

There is one chargeable flag can unchecked under project module, the task number will not visible. However, it impact accross iproc, AP,project and other modules. As user only want them not visible under expense UI, but not for other modules.

Is there any other options ?

After disable the chargeable flag:

OIE: the task no. no longer visible

Iproc: the task no. no longer visible- but user still want it to visible