Their dads played together at the 1991 World Cup and Allan Alaalatoa wants to channel his Samoan heritage and team up with Scott Sio in the ACT Brumbies' front row.

More than 20 years after Vili Alaalatoa was part of Samoa's giant-killing World Cup team, Allan will get his chance to impress after signing an extended player squad contract with the Brumbies.

Wallabies and Brumbies prop Scott Sio's dad, David, was Vili's teammate in 1991.

Now giant teenager Allan - a former Australian under-20s front-rower - wants to continue the family tradition.

''My dad is my role model, he always helps me out and if I go down that path I'd be very fortunate,'' Alaalatoa said.

''I grew up with Scott and his younger brother … he's helped me out a lot and it's good to have a relative down here as well.

''Islanders have big families. We played together in the junior ages and we've always been involved with each other. Scott is giving me his wisdom, he knows a lot and hopefully he gives me some tips so I can play alongside him next year.''

The Brumbies have finalised their five-man extended player squad for next year's Super Rugby campaign.

Alaalatoa is a 125-kilogram, 182-centimetre prop from Sydney trying to force his way into the Brumbies' front-row rotation.

Jean-Pierre Smith, twin brother of Brumbies prop Ruan, has also signed a contract with scrumhalf Michael Dowsett and Stephan Van Der Walt, securing one-year deals.

Western Force discard Lachlan McCaffrey hopes his Canberra move can relaunch his career as he aims to prove he can handle Super Rugby. McCaffrey played seven games with the Force last year, but was left on the outer when Michael Foley took over the coaching reins last season.

He's had to take a step back from a full-time contract spot to join the Brumbies extended player squad.

''When the guys were playing on a Saturday, I was in the gym getting myself ready,'' McCaffrey said of his year with the Force. ''My No.1 focus is trying to get in the [game-day squad] as many times as I can, it doesn't matter if you're on an EPS deal or not contracted.

''I see some opportunity here, some great coaches and a successful team and I see a huge opportunity to become a better player.''

Since the extended player squad was introduced in 2012, three Brumbies - Sio, Jesse Mogg and Scott Fardy - have gone on to play for the Wallabies while four have full-time Brumbies contracts.

Brumbies extended player squad: Lachlan McCaffrey (back row), Allan Alaalatoa (prop), JP Smith (prop), Stefan Van Der Walt (wing), Michael Dowsett (scrumhalf).