A Hussite noble priest in a Catholic realm would usually only be able to use their temples by the force of arms, unless the ones in charge of the temple were also Hussites. The problem is that we don't have the ability to declare a Priest from within our Church a heretic.
Yes, a Hussite noble preaching in a Catholic realm would be prevented from preaching by the realm's authority.
You can arrest priests.
What you are asking for is for the Catholic hierarchy to tell the peasants in an Orthodox realm not to listen to the Hussite priests, or even possibly in an Hussite realm! The temples are physical buildings within realms, the realms already have all the tools at their disposal to fight priests who use them wrongly.
