You can assign a custom script to activate when an object in an asset is -clicked.
To assign a custom script to an asset
You can now activate the script by either -clicking an object in the asset in the scene view, or
-clicking the asset or an encapsulated object in the Outliner and selecting Asset from the pop-up menu.When running a custom script from the Outliner, the script name does not appear in the pop-up menu itself. You only need to highlight the Asset menu and then release the mouse button to activate the script.
A script must be located in your script path (environment variable: MAYA_SCRIPT_PATH) to be eligible to put in the Rmb Command field.
Do not include the extension (for example, .mel for a MEL file) in the script name when entering it in the Rmb Command field.
One way to use this attribute is to assign a script that adds a custom menu for a specific asset to the existing pop-up menu that appears when you -click an asset in the scene or in the Outliner (in the Asset section of the pop-up menu). An example of such a script named containerRmbMenu.mel is included with the Maya default scripts. You can find it in your Maya install directory under scripts/others.