@mbudd10195 

In GC, set up a liability account called 'Due to Lawncare'.  Split the deposit in GC: $3K to your bank account and $7K to the newly-created 'Due to Lawncare' liability account.  Then issue payment to Lawncare and assign the 'Due to Lawncare' liability account to the payment.  Then, deposit the $7K in Lawncare as if it had been received from the customer.  You can make a note in the memo of the invoice to indicate that the customer's payment was made to GC, hence why the bank deposit is coming from GC and not the customer.