The additional code is not part of the theme and it required effort of a few hours for the development. In case you would like to go with paid support please feel free to let us know so that we can exclusively develop the code for you or you can find the widget that provides such facility.
GeM is solely for user verification and to apply e-signing on the documents. The e-sign is at par with Buyer Registration on GeM is divided into two categories: a. Primary User: In off-line contract to the Seller directly based on the outcome of e-Bidding / own Last Purchase Price; rates on other e-commerce websites etc.