RESTfull: POST variables from trigger

I need to do a POST-webhook from automation. Which variables to be sent will depends on the trigger.
Like:
In some cases: vertical, horizontal and move and in other cases just left or right
This works as long as the variable to be posted is defined in the rest_command:

  url: "http://username:password:myurl/action.cgi?move=true&vertical={{panVer}}&horizontal={{panHor}}"
    method: POST
    content_type: "application/x-www-form-urlencoded"

Are there anyway to handle this without make a dedicated rest_command for each unique combination of variables?

The template that you can define for url can be as complex as you want and for example include if statements. Maybe that helps distinguishing the various options?