Using a string of text to determine client name

I’m looking to auto-fill a client name field based on a unique string of 4 characters that will appear within a job title.
For example, if a job title is EXTORSEPT21, I want it to be able to see the “EXTO” part of it and print the result “Example Toyota,” while a job title of EXHYSMOCT211 would see the EXHY and result in “Example Hyundai.”

Currently, I’m finding some luck using the SUBSTITUTE command, but the output keeps the rest of the job title as part of the result and I can’t subtract characters from this result as the job title won’t always be a certain amount of characters. I’ve also tried an attempt at using IF and LEFT commands to pick up on only the first 4 characters and match it to a code, but I must not be structuring it correctly.
I also don’t know how to accomplish this for a multitude of different clients.

@StunWar

If you share your formula text we can probably help.

Jim - The Monday Man