For inactive GL departments, edit the department and remove the 'Department active' option. This will set the department and all associated account to be Inactive. Then set your Account finder grids to 'show active records only' in the grid column editor to hide all inactive accounts. This is done by double-clicking on a grid title bar.

If double-clicking on a grid title bar does not load the column editor for you, your Adagio system administrator has not granted you access to editing the grids, so you will have to ask them to either grant you access or change the active records setting for you.