Yes, you can do it via iCal if the other application allows an iCal connection. Below is the help article explaining the process https://www.tokeet.com/help/ical-connections/connecting-ical-channel

Don't waste your time and effort with Holidu integration they cover the UK

@Leonardo-Martinez Hi. This is actually already ticketed, and we have been in touch with the RemoteLock team. However, COVID has set the development of this integration back some months. I can not give you a timetable for when it will be released. We already began work on the integration, so when we are able to restart development, it will need to be beta tested before release. When that will be in unclear. We will make an announcement before we begin the closed beta. Thank you for your patience.