Standard SAP does not support Special Stock E (Sales Order) and Q (Project Stock) with 541 Movement type.
So, if you want the Stock to be consumed from the special stock during Subcontracting GRN, you have to perform 311 E Storage location to Storage location transfer (If required, you may create the separate storage location for this purpose).
If the Material is Excisable,you need to create a Subcontracting Chalan with reference to 311 E Material document. Movement type must be maintained in the Subcontracting Movement type groups.
Depending on the Individual / Collective Indicator in Material Master ( for Component) MRP4 View, system consumes the Stock during Subcontracting GRN for the Components.
If the indicator is set to "2" then the Stock will be consumed from the Stock provided to Vendor. If it is set it in any other way i.e.. Blank or "1" then the stock will get consumed from the Special Stock (transferred with 311E)
You can take the decision as per your business need. If you want the stock to be consumed from Subcontracting stock, you can normally use MB1B / MIGO / ME2O 541 Movement type with out Special stock.