Most pages will just have one Rover IDX shortcode - rover_idx_full_page or rover_idx_results, for instance.  But in the unusual situation where you have multiple Rover IDX shortcodes, and you want to make sure that one search panel drives a specific results area on that page.

For instance, these shortcodes will draw a search panel, and also draw a table of the active agents listings.  Because they are grouped, and the listing_agent_mlsid value is not part of the search panel, when a visitor makes a selection in the search panel, the listing_agent_mlsid will be ignored, and only the values set in the search panel will be observed:

[rover_idx_search_panel  group="sfi_latest_listings" prop_types="condo"]
[rover_idx_results_as_table group="sfi_latest_listings" prop_types="condo" listing_agent_mlsid="*"]

Just include the same group="name_that_links" value in both shortcodes, and you have linked them together.  It doesn't matter what you name it, as long as it's the same value in both shortcodes.