Fire event with variable in name?

I have a dropdown, and I have an automation that fires when it changes. That part works, but I then want to fire an event based on the dropdown’s value. If the dropdown is “out”, then fire “master_bed_out”. If the dropdown is “sleep”, then fire “master_bed_sleep”. The below doesn’t seem to work; it instead fires an event with no substitution, so literally firing an event named "master_bed_{{ states('input_select.masterbedroomstatus') }}" instead of “master_bed_sleep”.

Is there a way to make this work without resorting to a lot of “if” statements? I’ve searched all over for a similar example but can’t find one.

alias: When Masterbedroomstatus changes
description: ""
trigger:
  - platform: state
    entity_id: input_select.masterbedroomstatus
condition: []
action:
  - event: master_bed_{{ states('input_select.masterbedroomstatus') }}
    event_data: {}
mode: single

I don’t think the event key accepts templates, but you can use them in to define the output of keys in event_data.