SPD 2010 Approval Workflow multiple approvers (based on condition)

I’m working on building an Approval workflow in SPD 2010 for a resource calendar. I’m somewhat experienced in some areas on workflows but I’m running into issues on how to set it up. I apologize if there is already a thread for this.

Based on 1 specific field I want the current item to require approval from just only SP Group 1 if the field is ‘negative.’ If the field is ‘positive’ I want the item to require approval from SP Group 1 and SP Group 2 in serial.

What is the best way to go about putting this together?

Thanks for the help!