“Commando musicians are infiltrating the island.The Concerts in Waterfront Park audience will witness a two-pronged attack July 18, as the featured ensemble plays both fiddle tunes and jazz.We are individuals highly trained to deal with tense, dangerous musical situations whose special assignment is to penetrate deep into suburban middle class sensibilities, drummer John Lester said, somewhat tongue-in-cheek.The covert operation’s been in the planning stage for several weeks, according to Island Music Teachers Guild organizer and guitarist Alan Simcoe – ever since the park district called and extended the invitation to play the summer concert series.The approach is unique, because while the musicians who belong to IMTG share studio space and advertising, they’ve never before shared a stage, Simcoe said.Small sub-groups like the Alan Simcoe Trio may play together, but the whole IMTG membership doesn’t normally assemble. The strong individuality of IMTG members may explain their eclectic approach to a concert that will feature Caribbean and Brazilian music, as well as straight jazz, folk and classical. If you had a theme, it would be planned improvisation, Simcoe said. Those of us with a more formal bent are rehearsing, but some of us are not rehearsing, on purpose.The particular form of jazz the non-rehearsing group will play is completely improvisational, Lester said.It’s a lot of fun to do, he said. One of the musicians sings a tune they compose on the spot and the rest of the group improvises on it.Despite musical disparity, IMTG members practice peaceful co-existence in their shared studio space on Madison. Members can use the studio spaces to teach, turning over a portion of the tuition to cover the rent of the building. The IMTG planned the concert to coincide with the group’s week-long summer music camp for high school and middle school kids. The IMTG wanted the students to have the opportunity to hear them play. The kids will have a chance to shine at a recital, 10:30 a.m. July 21 at the Pavilion, and Wednesday night spotlights the teachers.We’re doing some pretty good stuff, drummer John Lester said. Stuart Williams is playing – he’s got more awards than I can even name. He’s a real luminary in the fiddle world. If you want to fiddle around, he’s the guy to call.Despite the fun of sometimes playing in small ensembles, the performers usually lead busy lives that keep them apart. We see each other in passing at the IMTG space, Lester said, but we’re too busy to hang out.This gig is our chance to romp and stomp. We’re going to throw all that good energy over the audience like a big net. And they better watch out; we take no prisoners. “