The default "Menu" plugin that comes with CoolMart is not very ideal for listing too many items. And it doesn't support "variations". Only level-2 and level-3 are supported. What you actually need is a "Mega Menu" module..
There are 3rd party Mega Menu modules for joomla (google it). They are standalone modules and work with any Joomla Template. But this time, the "Integration" will be too hard though. You should contact with the developer sand have them integrate the Mega Menu Module to your site.
Advanced Method: Alternatively, you can create a "Custom HTML" module and publish that module in the "Menu" position. Module name will be the "parent-menu-item" and its content will be displayed inside the dropdown. Browse the CoolMart live Demo demo.flexiblewebdesign.com/coolmart/index.php and see the last menu-item ("Custom HTML"). In that "Custom HTML" module, you will basically manipulate the menu-items and put your own custom HTMLs in it (menu-items won't be automatically generated, so make sure to enter the itemID's correctly for child-items)
The problem is, you can't put the "custom HTML" menu-module in between the ordinary parent-menu-items. It will be listed in the last position. To avoid it, disable the ordinary menu-module and use "Custom HTML" modules for all other parent-menu-items as well. You can sort those modules within the "menu" position and put the "RECAMBIOS" in the 3rd position.
But i would recommend you to go with the "3rd party MEGA MENU module", it will be much easier for you.
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