Modifying a digital sketch may require multiple selections before a particular editing tool can be applied. Especially on large interactive surfaces, such interactions can be fatiguing. Accordingly, we propose a method, called Suggero, to facilitate the selection process of digital ink. Suggero identifies groups of perceptually related drawing objects. These "perceptual groups" are used to suggest possible extensions in response to a person's initial selection. Two studies were conducted. First, a background study investigated participant's expectations of such a selection assistance tool. Then, an empirical study compared the effectiveness of Suggero with an existing manual technique. The results revealed that Suggero required fewer pen interactions and less pen movement, suggesting that Suggero minimizes fatigue during digital sketching.