Need custom action to work on click of tab for Embedded Component!!

Hi Experts ,

I have one requirement , where in I need to Call an External Web service , when we click the embedded component , which is obviously another custom B.O , I am able to call this through a custom button , but can the same action be called when we click the embedded component tab.

Please advise, or share links/documents if any..

Thanks,

Daljeet