Convert strConflictedYesReviewers data into a single object which is grouped by ownerid and then gro

Convert strConflictedYesReviewers data into a single object which is grouped by ownerid first and then groupby opportunityid which contains array of response.

I get a dynamic string(strConflictedYesReviewers) which contains multiple user recordswhere each record is separated by semicolon and then each record represents ownerid and opportunityid separated by asterisk.

const strConflictedYesReviewers =...

Convert strConflictedYesReviewers data into a single object which is grouped by ownerid and then gro