Is it possible to set a temporary progoram token value on a form submit.

We can do this now with the API, when requesting a campaign we can pass overrides to the default tokens in that campaign.  We use this to pass fields through for emails that wew don't need stored in the lead record clutering up the screen when reps look at it.  

We are converting to embedded forms and I'm jsut trying to figure out if theres a similar way to pass temparay data back with the form without having to create new custom fields.