Applying common monetary rule

Hello,
My aim is to apply a monetary rule simultaneously to 3 countries in one script.
Each country has it’s own supply and demand curve and it’s own shocks.
A script for one country seem to be as follow:
var y, pi, br, tcn;
varexo ey, epi, ebr, etcn;
parameters a1, a2…
parameters values
a1=…
a2=…
alpha=-0.5
beta=-0.5
model;
y=…
pi=…
br=gbr(-1)+alphay+beta*pi+ebr;
tcn=…
end;
check;
steady;
shocks;
var ey; stderr 3.74;
var epi; stderr 0.28;
var etcn; stderr 0.88;
end;
stoch_simul(irf=40);
As I said, my aim is to get a program in one script where the same monetary rule (br) is applied to 3 countries at the same time.
Any help?
Thank you in advance