New mare hounding gelding for sex

[kobi]

I bough a rising 6 year old mare 2 weeks ago who I'm struggling to integrate into my herd. I have a 10 year old cheeky retired gelding and one very old mare. Both the new mare and my gelding are fine turned out with the older mare but the new mare has taken a real shine to my gelding and follows him around and badgers him until he mounts her - which he does (I've had him rig tested and he's not a rig - he's been out with other mares without this problem - fortunately being retired he doesn't have shoes on). Any ideas about what I can do to get them all out together? The new mare seems to have been in season since she arrived and whilst it doesn't seem to affect her temperament or rideability it isn't helping matters with my gelding.

 

[Polonaise]

My gelding (yes he's been rig tested) doesn't just mount the mares (if you know what I mean). He tends to get the message that the older mare isn't really up to it despite all her flirting but him and the younger one (she's still 20) go at it whether she's in season or not if she's in the mood. She has a reputation of doing this with other geldings as well so don't think it's entirely his fault, just embarrassing as we have a footpath through the field that the local primary school kids use!
they may well calm down after a while, mares often come into season when herd dynamic changes and their first season of the year is often longer anyway.