AMX adds the ability to run each map with its own set of custom settings. Simply add a config file for each map or type of map in the amx/config/maps folder. The file is named after the map, but with a .cfg extension. For example, if you wanted a custom configuration for the map de_aztec, you would create de_aztec.cfg.
You can also create configs for just cs_ or de_ or any type of map. Below is an example of the contents of prefix_fy_.cfg. This config will be run on any fy_ map, such as fy_snow, fy_poolday, etc..
This is an example but you need to know as lot of maps config files are already inside each package (for CS and DoD), including these files named too: de_aztec.cfg, prefix_de_.cfg, prefix_fy_.cfg, etc.
Now let's say only on the map fy_iceworld you didn't want to allow flashbang grenades to be purchased, or the map to be extended. The above config will be run, setting the freeze time and friendly fire, then the below config will be run setting the weapon and voting restrictions as well.
As long as your server is set to run the server.cfgAdd mapchangecfgfile server.cfg to your server.cfg on each map change, then the default settings will be restored on each map. That is, unless you have a custom config for the next map!