Include Additional information about user in Confirmation Email


I was wondering if it is possible to include additional information relating to the user, in the confirmation emails.

It is similar to the CLIENT placeholder feature.

The below are the only placeholders that I can use,

For the above email subject and message contents, you can use the following placeholders which will be replaced by their real values: SITE_NAME, CLIENT, SERVICE, SERVICE_PROVIDER, DATE_TIME, PRICE, DEPOSIT, BALANCE, PHONE, NOTE, ADDRESS, CITY, EMAIL (Client's email), CANCEL (Adds a cancellation link to the email body)

I have a different field that is unique to each user in their profile. Is there a way I can have that unique field in each confirmation email?

Maybe I can just put the id of the field in their profile as one of the above placeholders that I don't plan on using (Price? deposit?) - Unsure if or how that works.

Please let me know if this is possible.