@Artem-Lavrynenko - unfortunately I don’t work for Suunto so can’t tell you if they would or wouldn’t - but I suspect wouldn’t - as not enough demand.
Note that my suggestion on how to run it via manual lap times will work in this regard. if you were previously late, or for some reason the gun is early (shortened sequence etc) - then press manual lap ASAP post gun. You can then see the lap timer from your current manual lap and base the start gun off that.
i.e. you started at 15min gun. 5min gun comes 11 mins after start gun, so you instead of leaving start running you press manual lap, this starts a duration count from 0. So you now have total duration running in background, and a manual point at 11mins. When the start gun goes 5 minutes later - you can see that from the manual lap point, you cross start and press manual lap. Your total duration will show 16mins, have a manual lap(ML) start at 11mins and at 16mins. You can then press ML at end of race, at end of each leg etc depending on what you want to time and record. When you view the ML points later on the map you will be able to see and confirm what each point was, asssuming you can’t remember.
Am assuming your suunto/watch can do this? I know the S7 can as do this for some of fitness activities (unfortunately do not sail anymore).
Not ideal but very workable and sort of how we used to do this with the old casio watches which only had start, stop and split. Crew had to keep a note of the timings on a whiteboard.which we would later transcribe into notepad along with map of sailing area and try and work out track onto map with notes and comments around wind and wave conditions and the impact on the sides of the courses. Always very useful when next sailing in same place and weather conditions are similar as could review what worked, where expected bends, holes etc were and then test them out prior to the race (we were usually out 1-1.5hrs before a race checking and testing potential course). Also useful to note if wind conditions changed and a similar shift occurred in a later race. Helped me a couple of times from being caught on wrong side of the course.
Would be soooo much easier now with current tech to do similar.