Stock removal - partial quantities first

Hi Experts,

  We have a requirement to build partial quantities first stock removal rule for following scenario: For ex: there is order with 61 EA. So, we have storage

  of goods 50 EA, 12EA, 11EA, 10EA , 1 EA and others quantities as well. So, system has to make efficient picking with partial quantities first. How can   I build that rule and requirement to meet this scenario. Can you please help me in this?

Thank you...

Srini