It absolutely is! You can use the "Looking for Group" or "LFG" chat to look for teams. Type /lfg followed by a brief message.
XP in teams, which is what pays off your debt, can vary. Technically, you only get a cut of the XP your team generates, since it gets divided between all team members, but at the same time, you are facing off against more enemies and tend to defeat them faster. In general, though, you do tend to get XP faster, (thereby paying off said debt), faster while on a team...