Hi Raul,
Did you tried the BADI to extend BP header search to filter out values - BADI_CRM_BUPA_IL_SEARCH_EXT.
There is a method IF_EX_CRM_BUPA_IL_SEARCH~FILTER_RESULT to filter out the result list.
Also, a quick check on this Set default values on a search view looks like your exact requirement.
Thanks,
Ravi