Ideally lambs should be weaned into a clean worm free paddock. But on our other block, we only have 3 main ones that are large enough. One has our crossbred flock, one our stud ewes and lambs, and the other is being rested.
We will wean at the end of January, so one option is to put the ram lambs, (which will soon start working) in the fresh paddock, then put the stud ewe lambs with the crossbred mothers, and the crossbred ewe and wether lambs with the stud ewes.
There is an additional advantage in this, the weaners settle much quicker when they are running with the adults, and we like to feed a few sheep pellets at this time, so that the adults teach the lambs to come for these,  useful in times of drought. It is a more natural way, not, say, having a town with only teenagers, "Lord of the Flies" style.