Index/Match with Multiple Criteria and Multiple return values

See attached workbook. Formula begins in cell F2 on down. Basically, it uses INDEX/MATCH to return a claim number from Group 2 where Group 1 has a date that falls between the Group 2 dates. It works fine to return one value, but, in instances of where I have multiple matching values, how do I return them both? (or even more)?

Can they be concatenated in the same cell separated by comma, or placed in the next cell over? Either way I am fine with. Thanks.