Need to filter values of a combobox of EP Page

Hi everyone,

I need to filter the values of a combobox on my EP page.

I tried adding look up method on the field of the dataset but couldn't achieve it. I tried with security policies but again couldn't get the result.

Please find the below screen shot of an EP page where I've combo box called "Loan Type". Loan type values are coming from another table. I just need to filter some values, when user goes and select the loan type.

Thanks guys,