Convert triplex to quad in Camden County, NJ?

Hey, So I’m looking at an off market triplex to purchase in Camden County, NJ. All units are 3 bed 1 bath and the largest apartment is 2600 SF so I wanted to see if maybe I could split that unit into 2 units. Can anyone provide any insight on this? I’ve never done anything like this before. The purchase price would be around $250k, property taxes are $8,300, and rents are $3500. Market rents should be about $1300 per unit+ or $3900+ total so current rents are below market Thanks!