Why not just check in your code if(items == 10 && players == 3) and then set a boolean which you check in the itemDef.

Some like:
PHP Code:
if(items == 10 && players == 3)
{
    
player setClientCvar("show_item10"1)
}
else
{
    
player setClientCvar("show_item10"0)

PHP Code:
dvartest "show_item10"
showDvar"1" //not sure if with or without quotation marks 
I know you want it to be easier, but I have never seen a double dvar check in menus. And this is the easiest way that by now has popped into my mind.