Sub sequence generator

Hi all,

is it possible to expand the sequence generator to sub keys? At present this is only possible for one key. I think something in this way

aTab{@pk1;@pk2;xx}
[1; 1;...]
[1; 2;...]
[2; 1; ...]

and so on...

This is important, when we need a compound key which is logically connected the the first sub key.