You can change the map_parameters.. But if you wan't to change only 1 round you can't do it. When you change this you can't come back at least you restart the map..
PHP Code:
#include <engine>
#include <amxmisc>
#include <amxmodx>
public plugin_precache () {
//If info_map_parameters exists
if (find_ent_by_class(iEnt, "info_map_parameters"))
//Change the value "buying" to 3:
//So you know, info_map_parameters is an entity that with their
//settings you can change the bomb radius and the buy
//The "buying" parameter has 4 values:
//0- All can buy
//1- Only CT can buy
//2- Only TT can buy
//Neither can buy
DispatchKeyValue("info_map_parameters", "buying", "3")
else {
//If the entity doesn't exists
//I create the entity, i set the buying value in 3 (previously explained) and i spawn it
ENT_CLASS = create_entity("info_map_parameters")
DispatchKeyValue(ENT_CLASS, "buying", "3")
DispatchSpawn(ENT_CLASS)
}
}