I like Sally's idea, but as that doesn't seem to be possible, how about this - could you take out your existing wether and put him with the new lad somewhere, maybe even shut in together for a week, away from the rest of the flock? That way he will bond with one animal who is also already a part of the existing group, so he will not be lonely and perhaps the rest of the group will accept the new lad more quickly if he comes in with a chum they know. This has worked for us in the past with ewes - give the newcomer a pal within the flock and it then becomes a member more quickly. Two together will chum up much more easily than a group v a single newcomer. It is pitiable watching a single newcomer moping miserably for many months on its own.