Skipper Gareth McAuley, Owen Garvan, Veliche Shumulikoski and Alex Bruce have all joined up with their national squads as the season enters its second international break of the season.
McAuley's Northern Ireland take on Slovenia in Maribor on Saturday with San Marino at Windsor Park next Wednesday. McAuley currently has 11 full caps.
Garvan and Bruce are in a Republic of Ireland fringe squad playing a "challenge match" with Nottingham Forest on Thursday at Dalymount Park, Dublin. No caps are being awarded for the game.
The midfielder is also in the U21 squad for a friendly in Lithuania next Tuesday. If he plays, Garvan will win his seventh U21 cap.
Bruce, who has one full cap, is in the senior Irish squad for their World Cup qualifier with Cyprus at Croke Park, Dublin next Wednesday.
Veliche Shumulikoski is in the Macedonia squad for their Group Nine World Cup qualifier with Iceland in Reykjavik next Wednesday.
Meanwhile, boss Jim Magilton says his experienced Premier League summer signings are having a positive effect on the club: "They have raised the quality and the profile and raised the tempo in training.
"They have all been in winning dressing rooms and have that real inner belief. It has slowly seeped in and will get better with confidence and with winning games of football.
"Certainly the manner in as much as they way they conduct themselves is all top class. They have all played at the highest level and we all want to get back there.â€Â
Elsewhere, former Town chief executive Howard Wells is reported to be a leading candidate for the same job at the FA. Wells, who is currently Northern Ireland's chief executive, was with the Blues for nine months between October 1999 and July 2000.
Town chairman David Sheepshanks has also been linked with the role of FA chief executive, which Brian Barwick is set to vacate at the end of the year.