Hide and Toggle function

Hide and Toggle function

Hello frnds.........
I am trying to collapse and expand links. My format is like this
mainlink1
-->sublink1
-->sublink2
mainlink2
-->sublink1
-->sublink2
Initially my sublinks is hidden when i clicking on mainlink it's expand.I am using jquery hide and toggle function. But My problem is when i click on sublink my mainlink is collapsed but i want to expand my mainlink until i click on other mainlinks.
Plz anybudy help me............