Can you use string functions in a PXSelector?

I have a UDF UsrCustomerID.

I originally used this for my DAC

        #region UsrCustomerID
        [Customer]
        [PXUIField(DisplayName = "Customer")]
        [PXRestrictor(typeof(Where<BAccount.parentBAccountID, IsNotNull>), ICSMessages.ParentAccount)]
        public virtual int? UsrCustomerID { get; set; }
        public abstract class usrCustomerID : PX.Data.BQL.BqlInt.Field<usrCustomerID> { }
        #endregion

I wanted to have access to the DescriptionField of the selector, so I tried this (which works)

        #region UsrCustomerID
        [PXDBInt]
        [PXUIField(DisplayName = "Customer")]
        [PXSelector(typeof(SearchFor<BAccount2.bAccountID>.
            Where<BAccount2.type.IsEqual<GetICSCustomerType>.
            And<BAccount2.parentBAccountID.IsNotNull>>),
                typeof(BAccount2.acctCD),
                typeof(BAccountCRM.acctName),
                SubstituteKey = typeof(BAccount2.acctCD),
                DescriptionField = typeof(BAccount2.acctName))]
        [PXRestrictor(typeof(Where<BAccount2.parentBAccountID, IsNotNull>), ICSMessages.ParentAccount)]
        public virtual int? UsrCustomerID { get; set; }
        public abstract class usrCustomerID : PX.Data.BQL.BqlInt.Field<usrCustomerID> { }
        #endregion
 

This is what is being displayed after selecting a customer.  NOTE this is NOT a segmented field.  My client is creating customers and manually putting a suffix in the account CD.  It looks like it is segmented, but the AcctCD in the BAccount table is just a string “PT00019-PLN06969”.

I want to override the display on the screen to show a “substring” of the Customer number.  I just want to show “PT00019” in that field.

I’m thinking there might be a way to use a SubString function on the DescriptionField like this:

DescriptionField = Substring(typeof(BAccount.description), 1, 7)) but that doesn’t compile. 

Is this even possible?  I don’t want to tell my client is cannot be done if it can.