Syntax Misstake for Simple Conditional Derived Column Expression

Greetings,

I need assistance in correcting my Syntax. I have a new column that I named facility, and I’d like to place the facility initials in that new column which are contained within the ID field.

This expression works (but it only pulls one 1 of the 3 facilities)

ID == "DRMC"?  "DRMC":""   (This one works by itself)

I tried to nest all 3 facilities within this expression but it is not working for me.

ID == "DRMC"?  "DRMC": (ID == "FLH"? "FLH:(ID == "FCH"?"FCH":""))

Thanks in advanced for pointing me in the right direction