If that doesn't work, then try to get XP, and when you're gonna level up, then you go to a meadow with many barbarians and walk straight into them and then before any of your or the barbarian minions die, you choose the missionary upgrade. When you do that, the barbarians and your minions will stop fighting, and they (the barbarians) will follow you in this case into the meadow where your castle lies (you don't need a castle or a meadow to do this). They will sit there and fight allies and enemies that come in rage.
NOTE: For this to work, you must not have max XP, not have the missionary upgrade, you have to stay with your trees and corn and your allies/enemies must not have the missionary upgrade.
Ideas
Maybe you should talk to them? I feel very intimidated when a team mate sits in their castle "shouting" at me to go away.
If that doesn't work, then try to get XP, and when you're gonna level up, then you go to a meadow with many barbarians and walk straight into them and then before any of your or the barbarian minions die, you choose the missionary upgrade. When you do that, the barbarians and your minions will stop fighting, and they (the barbarians) will follow you in this case into the meadow where your castle lies (you don't need a castle or a meadow to do this). They will sit there and fight allies and enemies that come in rage.
NOTE: For this to work, you must not have max XP, not have the missionary upgrade, you have to stay with your trees and corn and your allies/enemies must not have the missionary upgrade.