Question about one constraint

Hi everyone, sorry for bothering u.

I’m new with this programming language and I’ve problem with one constraint. I’ve to resolve this model, which is connected with the classical DEA one.
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In particular, I’ve no idea how to deal with the condition of j!=k.

The problem is that the coinstraint has to be linked with the objective function, so when I’ve to find the solution (f.e. e12*) the contraint has to be written for all j!=1.
For this reason, at each iteration, and for each solution, the number of contraints of this type should be (j-1) if j=1…n and n represents the number of DMU.

Has anyone any suggestion in order to deal with it?

Thanks in advance, hope u can help me.