I would pen the ewe with the greedy lambs away on her own with them. Firstly this stops them pinching off everyone else - and especially, stops them stealing all of any new mum's precious colostrum - and secondly, you will then be able to see if there's a problem with their own mum's milk supply. Which, given the behaviour you are describing, I strongly suspect there is. If so, you should be able to get such greedy guzzlers to take a top-up from a bottle; teach them to come to you for a feed night and morning, fill them up, and that will reduce the pressure on the other ewes.
The problem with leaving them be is that not only will they compromise any newborns by stealing all the new mum's colostrum before her own babies can get sufficient, but also by constantly raiding all the other ewes' udders they are likely to cause mastitis in one or more of them. Any ewe rearing twins has enough work to do producing milk for her own lambs, if she's being milked as well she's at risk of mastitis.