Gregg is hoping to stun pal Robinson with gutsy Dalriada
One of those intriguing sub-plots emerges from today's Danske Bank Schools' Cup semi-final at the Kingspan Stadium (2.30pm) as Brian Robinson and Rab Gregg - respective head coaches of Campbell College, one of the competition's big-hitters, and clear underdogs Dalriada - are former schoolmates from Cambridge House in Ballymena and have remained good friends ever since.
Not only that but the pair also played on the Cambridge House side which lifted the Subsidiary Shield back in the 1980s prior to both going on to study at the University of Ulster.
So, the two friends now find themselves going head-to-head with Robinson's Campbell the clear favourites to progress to their 40th final, and first since 2011, with the Belfast school still tipped as strong contenders to ultimately lift the trophy even though they had to work very hard to see off Methodist College in the quarters.
But Gregg reckons that Dalriada - whose one and only final appearance so far was in 1993 when they actually lost to today's opponents by a fairly hefty 46-13 - will not be found wanting when his squad encounter this Campbell side.
Indeed, Dalriada have quietly gone about their business to reach the last four and are more than ready to cause an upset.
"I'd expect us to have a very good game against Campbell," Gregg said before commenting on the Belmont school's tight triumph over Methody (Campbell won 11-10).
"We were actually surprised to hear that their game had been so close as we thought it would never have been like that.
"We haven't played them this year, and we don't have regular fixtures against Campbell, but we'll just play our normal game and our own brand of rugby."
The Ballymoney school are certainly no strangers to lifting silverware as they claimed the Subsidiary Shield in 2014 before winning the Bowl last season and now making the Schools' Cup semi-final offers more evidence that they are moving forward.
"The school have worked very hard on it over the last few years," added Gregg, who is currently in his second year overseeing rugby at the school after moving from alma mater Cambridge House.
One of several key battles which will catch the eye will be between Dalriada's experienced loose-head prop Aaron Christie and Campbell's highly regarded tight-head Tom O'Toole.
Coach Gregg will also be hoping that their pack can produce enough ball for out-half Angus Johnson and centres Stewart Moore and Denis Pasternak to work off.
Campbell, though, have a mighty looking team with O'Toole's power - he actually had a fairly quiet game against Methody's aggressive defence -just one of several key components to their side.
Campbell's pack also contains the hard-working Jack Barry Glendinning at No.8 - though they will be missing second row Matthew Crowther due to an ankle ligament injury - while their midfield is a combination of Nicolai Koplewsky's direct running alongside Jonny Haldane's pace.
Full-back Ben Webb will also punish any loose kicking with his ability to find space with ball in hand.
While also pointing out that the core of the side is the same as the Medallion Shield winning squad of 2013, Robinson said: "We didn't do ourselves justice in the way that we played against Methody in the quarter-finals.
"It was uncharacteristic of our style of play. Now we, as coaches, have to put the boys in a place where they feel comfortable and ready to perform."
Of Campbell's first Schools' Cup semi-final since 2012, he added: "It's good to get back though."