I am writing a paper about Emily Dickinson's ‘They shut me up in Prose –.’ The two characters of the poem are the speaker and an unidentified group only referred to as 'they' and later as 'themself.' When writing about the group of people, it is burdensome to say 'the unidentified group' or 'the oppressors' and so on, so I have been referring to them as they always in italics.
In a draft of my paper, I was declining the noun to fit the grammatical context, for instance 'being silenced by them,' but my professor said I should treat 'they' as one would treat the 'I' as people do in literary criticism and keep everything in the nominative case. This presents no difficulty for nominatives and seems fine for objective cases, but I'm a little stumped by the possessives.
I've been italicizing the four letters of 'they' and leaving the apostrophe s unitalicized to indicate that I am only treating 'they' as an isolated verbal element, which is why it isn't the much more natural sounding 'their.' An example is, 'the despotic arbitrariness of they’s actions.' It seems consistent, but also incredibly awkward. Is it wrong? Is there another option? What do people do in this situation for the 'I' in literary criticism?