How do I hide part of a field in a SSRS textbox?

I have a SSRS report where in one text box I want to only display part of the FIELD that populates the textbox.
For example, if the text in the field is "LASTNAME, FI - ID", I want to display only "LASTNAME, FI". So in the query I have Select LASTNAME + ', ' + LEFT(FIRSTNAME,1) + ' - ' + ID.
I can't just change the SELECT statement to leave off ID because I need that for grouping and sorting.
I changed the placeholder properties to recognize HTML tags
Something like:
Select LASTNAME + ', ' + LEFT(FIRSTNAME,1) +<font size= "3">' + ' - ' + ID + '</font>'
works, but I can't find a way to hide the ID
I tried:
Select LASTNAME + ', ' + LEFT(FIRSTNAME,1) +<div style="visibility:hidden">' + ' - ' + ID + '</div>'
References say that only certain inline CSS attributes are supported, so visibility must be one that isn't.
Any ideas, other than using one field for sorting and another for display.