nested repeating group

Imported from previous forum

[ original email was from serge pevzner - skasikhi@yahoo.com ]
A repeating group could appear anywhere in a message preceeded by a required fields (a count of followed groups and first field of a repeating group). But this is not sad for a repeating group inside of another repeating group which would be a nested repeaing group, to be anywhere inside of the outer repeating group, because an order of field of a repeating group must be in the order defined in spec. But a nested repeating group is actually is a repeating group and should have a behavior of a regular repeating group, so to be placed anywhere inside an outer repeating group. Is there possibility to add this feature to a nested repeating group to be placed anywhere inside of an outer group? thanks.