[TYPO3] Substitute nested data values in typoscript

[Lukas Mattsson]

How do variable substitution work in typoscript?

For example:
data = GPvar : tx_awanthrcompanies_pi1 | company_id
gives me the value 848, because the url contain the string 
tx_awanthrcompanies_pi1[company_id]=848

data = DB:tx_awanthrcompanies_companies:848:company_name
gives me the value "Annaskolan" because the field "company_name" of the 
record with uid 848 in the table tx_awanthrcompanies_companies is 
"Annaskolan"

data = 
DB:tx_awanthrcompanies_companies:{GPvar:tx_awanthrcompanies_pi1|company_id}:company_name
should give me the value "Annaskolan" but it doesn't give me anything

Best regards, Lukas