Here's an idea:
Marten and Dora have a fight over something, and Marten storms out. From miles away, the Vespavenger hears the fight through a tap she retained on their apartment. She Vespas to them, and starts kicking Marten's ass. Penelope looks up, in her apartment.
She rummages through her closet, and we see some fight and dialog between the Vespavenger, Dora and Marten, regarding her return.
Then...Pizza Girl shows up! She joins the battle alongside Marten and Dora, but then comes another blonde superhero, with an uncanny resemblance to Penelope. They discuss this during the fight.
They kick the shit out of the Vespavenger, and the cops take her away. Then Marten and Dora grab the two blonde superheroines, and they unmask them.
The new one is Penelope, and explains that she got tired of all the girls at CoD calling her Pizza Girl, so she created a new Superheroine secret identity. Meanwhile, Pizza Girl gets away, blocking her face. Marten claims the glimpse he got made her look like someone familiar.
The next Day, at CoD, Marty, Spookypants and Penny tell the story to Faye. Then, somebody walks in. Dora and Faye stare first, then Marten, and Penny is all 'What're you guys looking at?'
Dora's all like, to Faye 'You have to go talk to her'. 'Fine,' Faye says, 'I'll bring her her order.' Faye walks over to 'her' with her latte, and the big revel is next comic.
It's totally fuckin' Sara.