First, I'm going to make some assumptions:
- I'm assuming you can customize the New Item Form on the Calendar.
- I'm assuming you will use InfoPath Designer to do the Form customization.
- I'm assuming you have the administrative rights to create other Lists and manage the permissions of them.
If those assumptions are correct, here is what I would do:
Create 4 separate lists in the same site as the Calendar:
1a. FM Locations Lookup
1b. FS Locations Lookup
1c. CS Locations Lookup
1d. CoC Locations Lookup
NOTE: For this example, just use the Title column of each of the above lists to store the Location value.
Create 4 new Columns in your Calendar, each of which is a Lookup to one of the above lists. The value will come from the Title column of each of the above lists.
Edit your New Item Form in your Calendar, and place the 4 Lookups you just created on the Form where you would like them to show.
Click on any one of them, and click Manage Rules.
Create a Formatting Rule for each Lookup control similar to the following (let's use FM as an example):
5a. Condition: If SFI Standard does not equal FM.
5b. Action: Check the box that says "Hide this control".
The result of the above will be as follows:
When a user creates a new Item in the Calendar, none of the 4 Lookup columns will be visible (assuming there is nothing in SFI Standard yet). Once a user selects a value for SFI Standard, the correct Lookup will show. The lookup will contain the data from the list you connected it to when you created it.
Please let me know if I can provide more details.