example.cls

	public static void createNotification(Opportunity o, Id submitterId, String distOptions, String text, List<Id> workItemIds){
	
		List<CollaborationGroup> uList = [
			SELECT Id,Name
			FROM CollaborationGroup
			WHERE Name = 'Bridge Underwriters'
			OR Name = 'Term Underwriters'
			OR Name = 'Capital Markets'
		];
		Map<String,Id> um = new Map<String,Id>();
		for (CollaborationGroup u : uList){
			um.put(u.Name, u.Id);
		}
		Id distId;
		if (o.RecordType.Name == 'LOC Loan' || o.RecordType.Name == 'Single Asset Loan'){
			distId = um.get('Bridge Underwriters');
		} else if (o.RecordType.Name == 'Term Loan'){
			distId = um.get('Term Underwriters');
		}
		Id capMarketsId = um.get('Capital Markets');

		Id analystId;
		if (null != o.CAF_Analyst__c){
			analystId = o.CAF_Analyst__c;
		}
		ConnectApi.MessageBodyInput messageInput = new ConnectApi.MessageBodyInput();
		messageInput.messageSegments = new List<ConnectApi.MessageSegmentInput>();

		// distOptions: bridgeOnly, termOnly, capitalMarketsOnly, all
		if ( distOptions == 'loanOnly' ){
			System.debug('inside distOption loadOnly');
			ConnectApi.MentionSegmentInput mentionSegment = new ConnectApi.MentionSegmentInput();
			mentionSegment.id = distId;
			messageInput.messageSegments.add(mentionSegment);
		}
		else if ( distOptions == 'capitalMarketsOnly') {
			System.debug('inside distOption capMarketsOnly');
			ConnectApi.MentionSegmentInput mentionSegment = new ConnectApi.MentionSegmentInput();
			mentionSegment.id = capMarketsId;
			messageInput.messageSegments.add(mentionSegment);
		}
		else if ( distOptions == 'all') {
			System.debug('inside distOption all');
			ConnectApi.MentionSegmentInput mentionSegment = new ConnectApi.MentionSegmentInput();
			mentionSegment.id = o.OwnerId; // The ID of the user to mention.
			messageInput.messageSegments.add(mentionSegment);

			ConnectApi.MentionSegmentInput mentionSegment2 = new ConnectApi.MentionSegmentInput();
			mentionSegment2.id = distId;
			messageInput.messageSegments.add(mentionSegment2);

			ConnectApi.MentionSegmentInput mentionSegment3 = new ConnectApi.MentionSegmentInput();
			mentionSegment3.id = submitterId;
			messageInput.messageSegments.add(mentionSegment3);

			ConnectApi.MentionSegmentInput mentionSegment4 = new ConnectApi.MentionSegmentInput();
			mentionSegment4.id = capMarketsId;
			messageInput.messageSegments.add(mentionSegment4);
		}

		if (null != analystId){
			ConnectApi.MentionSegmentInput mentionSegment5 = new ConnectApi.MentionSegmentInput();
			mentionSegment5.id = analystId; // The ID of the user to mention.
			messageInput.messageSegments.add(mentionSegment5);
		}

		ConnectApi.TextSegmentInput textSegment = new ConnectApi.TextSegmentInput();
		textSegment.text = text;
		messageInput.messageSegments.add(textSegment);

		ConnectApi.FeedItemInput input = new ConnectApi.FeedItemInput();
		input.body = messageInput;
		input.subjectId = o.Id;

		if (null != workItemIds){
			ConnectApi.LinkCapabilityInput lci = new ConnectApi.LinkCapabilityInput();
			lci.url = 'https://cvest--full.lightning.force.com/one/one.app#/sObject/' + workItemIds[0] + '/view';
			lci.urlName = 'Test Link';
            
			ConnectApi.FeedElementCapabilitiesInput feci = new ConnectApi.FeedElementCapabilitiesInput();
			feci.link = lci;
            
			input.capabilities = feci;
		}

		ConnectApi.FeedElement fi = ConnectApi.ChatterFeeds.postFeedElement(Network.getNetworkId(), input);
	}