Conferences can be useful venues to solidify your current professional relationships, after all, maintaining and strengthening existing ones is important. Even so, still try to avoid the easy route of spending all your time with people you already know – as this sort of defeats the purpose of going to the conference in the first place.
An idea on how to manage your existing connections
If you know beforehand that certain colleagues are likely to hang around with you, try to draw clear boundaries - for both of your sakes.
Having existing dinner or lunch plans can be handy. Maybe say to your colleague: ‘I’m on a mission to meet and network tonight, but tomorrow I’m going to a session that I think we’ll both find interesting. Maybe we could catch up then?’