AutoCAD Plant 3D toolset Project Manager manages all the isometric drawings for you. It has separate folders for all the iso styles you need to create, and setting up the styles and the locations for these drawings is managed through Project Manager > Properties:
Isometrics are created by line number and are sorted by Iso style in the Project Manager:
Isometrics can be created just from a drawing, in which case only those piping components in that drawing will be extracted to the iso, or for the whole project. In this case the whole line (across several model files perhaps) will be extracted into the single isometric. Note that an isometric drawing may be split into several sheets. Each sheet will be a separate dwg.
Because the isometric is extracted from the 3D model, most CAD Managers do not allow isometrics to be edited in any way.
This prevents inconsistencies between the model and the isometric.