Nested Hash Problem

Dear all,   I have a hash serv_value => {60=>{"servicetype_id"=>4, "quantity"=>1, "amount"=>360.0, "narration"=>"GTT"}, 6116=>{"servicetype_id"=>1934, "quantity"=>1, "amount"=>42500.0, "narration"=>"HRT.BT SHUNT"}, 78=>{"servicetype_id"=>5499, "quantity"=>1, "amount"=>500.0, "narration"=>"LIPID PROFILE"}, 6477=>{"servicetype_id"=>5499, "quantity"=>1, "amount"=>500.0, "narration"=>"XRAY CHARGES"}, 152=>{"servicetype_id"=>5499, "quantity"=>1, "amount"=>90.0, "narration"=>"VDRL"}}

I want it to rearrange such a way that I should get

serv_value => {4 => {"quantity"=>1, "amount"=>360.0, "narration"=>"GTT"}, 1934=>{"quantity"=>1, "amount"=>42500.0, "narration"=>"HRT.BT SHUNT"}, 5499 => {{ "quantity"=>1, "amount"=>500.0, "narration"=>"LIPID PROFILE"}, {"quantity"=>1, "amount"=>500.0, "narration"=>"XRAY CHARGES"}, {"quantity"=>1, "amount"=>90.0, "narration"=>"VDRL"}} }

In this, I need to make a hash with key as servicetype_id.

Pls help me, Thanks in Advance, Avantec