Is it possible to change the sub-task numbering scheme so that it is a different level than tasks and remains in the context of the parent task?

i.e. If the Parent Task is 'JIRA-400' the sub tasks would be 'JIRA-400.1'; 'JIRA-400.2' etc. The current numbering makes it a little hard to communicate the context of the sub-task as it is possible to have 'JIRA-400' as the parent and then sub-tasks as 'JIRA-405', 'JIRA-500', 'JIRA-508' etc. This provides absolutely no context for the sub-tasks and makes managing and communicating that much more difficult.

Additionally as a sub-tasks is essentially a child task, it would be ideal if the number scheme reflected this.