Enforcing room time!

[MamaMoose1]

Hi, I have 10 and 5 year old boys, also a toddler, she is 19 months (just). My 5 year old always loiters around his sister and just generally is a bit in her face, to the point she gets upset. I've told him he needs to stop this and give her some space. My 10 year old is always bored and unless he is being entertained by a game/TV then he loiters around the house too, often wanting to wrestle with his brother, or running around, just being generally hectic and it is driving me insane. Sometimes I am on my own for a week, sometimes longer, as my husband is sometimes required to work away, the household is very hectic and things do need to change. I want to implement room time into their evening, they do share a room with very little space, so separate rooms may be better. Does anyone else do this? They won't go of and do anything constructive, they contain themselves to the sitting room (which is small) and it's getting too much to cope with everyday. Am I being fair by doing this?
Also just to add they have 25 minutes each, quality one to one time per night, where we do things together, read, chat etc.

Thanks for any replies!