According to the character list... <em>Abram/Abraham</em> is from the house of Montague, and <em>Gregory</em> (alongside Sampson) is a Capulet servant (they're the pair that provokes a fight with Montague in the beginning of the play) <em>Balthasar</em> is the loyal servant that brings news of Juliet's "death" to Romeo, so he's in Montague.
And of course, <em>Romeo</em> is the Montague heir/"prince"
I saved a child by getting beat up because 3 of these people were trying to jump this one person in front of everyone and ain’t no way i was gonna let that happen