Yep... again, we're talking about variable variables, though I don't remember where an example like this appears in the manual so I'll just give it to you:
$i = 1;
$total1 = 123456789;
echo "Total1 is: " . ${'total' . $i}; // Total1 is: 123456789
Same for having multiple variables:
$i = 1;
$group = 'numbers';
$type = 'total';
$numbers_total_1 = 123456789;
echo ${$group . '_' . $type . '_' . $i}; // 123456789