Tab from one subform to another subform

[Winnie]

I have two subforms built in one main form. The Tab order
only allows the tab go from the main form to the first
subform. when the tab finish the last stop of this first
subform it gose back to the first stop within this
subform instead of jumps to the first stop of next
subform. How do I make the tab jump from the last stop of
the first subform to the first stop of the second
subform? Please help.

Thanks in advance.

Winnie