How to parameterized xpath in Edit Element

Hi,

I am identifying element using Xpath which is: //a[text()='APPLICATION INDICATOR']/following-sibling::select

I want to data bing 'APPLICATION INDICATOR' with my local data column which named as 'mandatory'.

I tried following tricks but no luck:
//a[text()=$(mandatory)]/following-sibling::select

or
//a[text()=$mandatory]/following-sibling::select

or
//a[text()=mandatory]/following-sibling::select

Please help me to resolve this issue.