Single Valuation View FINSC_LEDGER

HI :- Need to understand regarding Single Valuation approach in FINSC_LEDGER, when we create a seperate ledger for Group valuation i.e. Currency 11 & 31 for Group valuation view.

Since only the Leading ledger is integrated with Controlling i.e. 0L & most of the client go for Multi valuation approach.

If i create a non-leading ledger as Group Valuation how will it be integrated with Controlling? Though i can assign the Controlling area/ Version ( Group Valuation with Ledger group)

My Question will the Non leading ledger be integrated with CO. we wont activate the COGM functionality.