IUICCON/ProcessSaveButtonBar - Avoid Save if custom error exist

HI,

While creating New Move IN/Out there is below guided process and then on SUMMARY we click on SUBMIT button.

New Contracts->Account & Payment Data->Summary

So now iam displaying some custom error messages as per requirement in "Account & Payment Data" tab from the message service class and when i navigate to SUMMARY and click SUMBIT button it still SAVE the contract even though this custom error message exits.

I want to Avoid saving if any custome error messages exist. I know i can check if any error message exist then do not call SUPER->EH_ONBT_SAVE_PROCESS but i don't want to do via this approach.