I would like to express the following in GAMS using its MAX(x1,x2,…,xn) function.

max {B(i,j)¦i in Ij} for all valid combinations of (i,j) where i={i1,i2,…,in}, j={j1,j2,…,jk).

So, the GAMS-determined result could be something like this

MAX(B(i1,j1), B(i2,j1), B(i5,j1)) =l= …

MAX(B(i1,j2), B(i3,j2), B(i4,j2), B(i6,j2)) =l=…

MAX(B(i3,j3), B(i5,j3)) =l=…

…

Is there a way to do this in GAMS?