Need assistance about automatic relationships

Hello,

I have 2 post types, Bid Requests and Bid Proposals.

This is a bid request single post sample https://www.kioubizin.mu/bid-request/i-need-a-contractor-to-build-my-house/

As you can see under the section “SUBMIT PROPOSAL” I have a form created in Frontend Admin to create a new bid proposal and added this form to the bid request single post page and you can see the form on the same link mentioned above.

I have 2 relationships fields (bidirectional relationship field) in the bid request field group in ACF, the relationship field is “bid_request_related_bid_proposal” and in the bid proposal field group, the relationship field is “bid_proposal_related_bid_request”

What I want to achieve is that, whenever a user submits the proposal form on a single request page, the post is automatically added as a relationship to the displayed request post without the need for the user to select the bid request post as relationship.