question

treenode networkCAlinks = Model.find("AGVNetwork>variables/controlAreas");

forobjecttreeunder(networkCAlinks)
{
    treenode link = a;
    ownerobject(link.value).as(Object).setProperty("MaxAllocations", 99);
}

Rather than manipulate the number of allowed allocations, you could also try to leave it at one and instead 'manually' allow further allocations.

If you overwrite the return value of the "On Request" event with a 1 (or, to be on the safe side the expression AGV.Request.Allow), the allocation will be allowed regardless of the limit set on the area/point. To block the request use AGV.Request.Block or -1 instead.