Initial concentration at the node, 1D, Solute transport, Porous media

Hello,

I have a pretty easy 1D model, governed by the solute transport equation. My idea is to coupled it with the geochemical software phreeqc. So I would like to treat the nodes of comsol as phreeqc cells.

So geometrically, it is mainly an interval, from L0 to Ln. I have subdivided the interval into small intervals placing point where a mesh point correspont.

Now I would like to give at each node point a different initial value.
Is it that possible? Or I just can choose a Domain, namely 2 nodes.

I have tried to give values at the nodes points using an initial value node and stating "Initial_Value*(x==Node_point)" where Initial_Value is the value of the concentration and Node_point is a point in the interval [L0, Ln]. Anyway it seems that Comsol makes the average between the neighbors and ignore my value.

I have tried different things but so far there is not a result that please me. I hope it is understandable.

Thank you