TI-TINA: how can I use non-trivial expressions to parameterize parts?

I have a design where I have a set of variables where I derive values of many resistors from. In ltspice I could use something like ".param Ra={Rb+Rc / g}" to calculate those based on the parameters I step and other resistors. Is there a way to do so in TINA? The part parameters dialog would not allow me to insert a symbolic value instead of a float.