Going away from the barn I would just ride out the spins. Keeping him moving forward and keep asking him to pay attention to you. Try serpentines, gait changes, halts, etc.
Going towards the barn this is what worked for me and buddy sour horses before. He would also try to rush home. I would turn towards home and ask for a slow calm walk on a loose rein. The second he sped up, I turned him around and we trotted away from the house. We did some serpentines, circles, etc, basically made him "work". Went maybe half a block, I turned around and again asked for a slow calm walk on a loose rein. The second he started to speed up we turned around and repeated the above manuevers.
To be honest I don't think you're going to get anywhere by popping him with the reins/crop/spurs when you want him to slow down and listen to you. What you want is him to calm down and pay attn to you. By using reins/crop/spurs in the way you're talking about all you're going to do is ramp him up. The problem is that he doesn't look to you as a leader and he doesn't trust you to take care of the problem (being away from his "herd") because you haven't yet proven yourself to be the leader of the herd.I would try all of this in a safe area relatively close to the barn to start out with, gradually move further away as he starts paying attention to you.
Another thing that may help is some basic groundwork. Really basic stuff here: walk him around on a lead, practice backing up, turn on forehand, yeild hindquarters, and things like that. I actually started this in the paddock where he lives. I tied the mare that he was/is in love with right outside the paddock and walked him around inside. I made him pay attention to me by not being predictable in my requests. Ex. Walk forward, halt, back up, walk, turn, halt, yield hindquarters, etc. After a couple sessions of this we moved outside the paddock boundaries while the mare was kept inside the paddock. Same type of groundwork. Then we walked up the driveway. Then I rode him away from the paddock. I only worked on the groundwork for about a week, everyday 10-20 minutes.
The groundwork should help prevent the problem from occuring in the first place while the first thing I wrote about is what to do if he does it while you're already riding him. If you're really committed to fixing this problem I would work on the ground first then take it to the saddle.
A very important thing: You need to stay CALM, don't let him ramp you up and get you upset. Keep your emotions under control. This will feed to him too. You'll feel like you're in control and he will respond to that even if only a little bit. At the very least it'll make any action you take hold a lot more weight with him.
Honestly I see no reason to separate them in their day to day living. In fact I think it's cruel. It's very healthy for them to have a herd they really enjoy being with. You just need to teach him that you are the leader and the most important person in the herd.