Or you can manually edit the ControlPointTemplates.con of your map, to make a flag only capable by one team. There are lots of maps where you meet this situation, for example on Omaha Beach the beach flag is only capable by Allies (team 2), here is a sample of ControlPointTemplates.con file :
ObjectTemplate.create ControlPoint beach
ObjectTemplate.networkableInfo ControlPointInfo
ObjectTemplate.setControlPointName Beach
ObjectTemplate.radius 41
ObjectTemplate.team 0 >> 0 means it is neutral at the beginning of the round
ObjectTemplate.spawnGroupId 4
ObjectTemplate.objectSpawnerId 4
ObjectTemplate.timeToGetControl 15
ObjectTemplate.timeToLoseControl 99
ObjectTemplate.onlyTakeableByTeam 2 >> only team 2 (allies) can cap this flag
ObjectTemplate.geometry flagbase2_m1
ObjectTemplate.areaValue 0
ObjectTemplate.minNrToTakeControl 2
ObjectTemplate.disableIfEnemyInsideRadius 0
ObjectTemplate.disableWhenLosingControl 0
ObjectTemplate.loseControlWhenEnemyClose 1
ObjectTemplate.loseControlWhenNotClose 0
ObjectTemplate.hasCollisionPhysics 1
ObjectTemplate.addTemplate AnimatedFlag
ObjectTemplate.setPosition 0/8.2/0
ObjectTemplate.setTeamGeometry 1 flagge_m1
ObjectTemplate.setTeamGeometry 2 flagus_m1
And that's an other flag on the same map :
ObjectTemplate.create ControlPoint commandpost
ObjectTemplate.networkableInfo ControlPointInfo
ObjectTemplate.setControlPointName Commandpost
ObjectTemplate.radius 23
ObjectTemplate.team 1 >> that flag is controlled by Axis at the beginning
ObjectTemplate.spawnGroupId 2
ObjectTemplate.objectSpawnerId 2
ObjectTemplate.timeToGetControl 14
ObjectTemplate.timeToLoseControl 13
ObjectTemplate.geometry flagbase_m1
ObjectTemplate.areaValue 50
ObjectTemplate.disableIfEnemyInsideRadius 0
ObjectTemplate.disableWhenLosingControl 0
ObjectTemplate.loseControlWhenEnemyClose 1
ObjectTemplate.loseControlWhenNotClose 0
ObjectTemplate.hasCollisionPhysics 1
ObjectTemplate.addTemplate AnimatedFlag
ObjectTemplate.setPosition 0/8.2/0
ObjectTemplate.setTeamGeometry 1 flagge_m1
ObjectTemplate.setTeamGeometry 2 flagus_m1
And you don't see this line : onlyTakeableByTeam, which means both teams can cap this flag.
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If I understand your second question correctly, you want to make a vehicle spawn only when a flag is capped, a kind of reinforcement. Once more you can use the code of other maps, on Alpenfestung, a King Tiger spawns at the airport if Allies cap the Church flag.
This is the spawner of King Tiger (ObjectSpawnTemplate.con) :
ObjectTemplate.create ObjectSpawner sidespawneraxistankheavy
ObjectTemplate.setObjectTemplate 2 kingtiger
ObjectTemplate.setObjectTemplate 1 none
ObjectTemplate.MinSpawnDelay 180
ObjectTemplate.MaxSpawnDelay 220
ObjectTemplate.SpawnDelayAtStart 0
ObjectTemplate.TimeToLive 45
ObjectTemplate.Distance 40
ObjectTemplate.DamageWhenLost 0
This is from the ObjectSpawns.con
Object.create sidespawneraxistankheavy
Object.absolutePosition 1061.17/30.7328/1903.38
Object.rotation -180.75/0/1.52588e-005
Object.setOSId 7
The number 7 in yellow correspond to the ID of the flag #7, if you check the ControlPointTemplates, you will see this :
ObjectTemplate.create ControlPoint broalleis_cpoint
ObjectTemplate.networkableInfo ControlPointInfo
ObjectTemplate.setControlPointName Church
ObjectTemplate.radius 5
ObjectTemplate.team 1
ObjectTemplate.spawnGroupId 7
ObjectTemplate.objectSpawnerId 7
ObjectTemplate.timeToGetControl 0
ObjectTemplate.timeToLoseControl 2
ObjectTemplate.geometry flagbase_m1
ObjectTemplate.setNetworkableInfo ControlPointInfo
ObjectTemplate.areaValue 50
ObjectTemplate.disableIfEnemyInsideRadius 0
ObjectTemplate.disableWhenLosingControl 0
ObjectTemplate.loseControlWhenEnemyClose 0
ObjectTemplate.loseControlWhenNotClose 0
ObjectTemplate.hasCollisionPhysics 1
ObjectTemplate.addTemplate AnimatedFlag
ObjectTemplate.setPosition 0/8.2/0
ObjectTemplate.setTeamGeometry 1 flagge_m1
ObjectTemplate.setTeamGeometry 2 flagus_m1
The King Tiger spawning on the airfield base is linked to the church, when Church's flag is controlled by Team 1 (Axis), there is no vehicle spawning at Airfield, however when it is controlled by Team 2 (Allies), a KT appears. This is how reinforcement works, I hope it is clear :s