Hi Ganesha,
This is definitely possible to do through Customization. What you would need to do is first copy the stock screen, and customize the Contacts grid contained on it.
While Editing the contacts grid on this screen, you will need to navigate to Step 2 of 9: Grid Columns, scrolling down to line with the Caption Phone / Email / Mobile. Beside this line, click on the Advanced button.
Here you will see some SQL code in the textbox labelled "SQL - the following script will be used instead of the original field" Here, you will want to elimiate any references to the viewContacts.Email field. The code will look like this once youve removed it. You can copy and paste this in (ensure to remove the code that was already in there)
'<b>' + (CASE WHEN viewContacts.Phone IS NULL OR viewContacts.Phone='' THEN '' ELSE + viewContacts.Phone END) + '</b>' + '<br />' + ISNULL(viewContacts.Mobile,'')
Finally, you will need to remove 'Email' from the second textbox labelled 'Filter Field(s)'
After this, save and Close, publish the screen and youre good to go!
Thanks Ganesha!
Regards,
Ben