Estimation Help

[Nouman]

Hello I am working on hedonic property value approach. I have four cross section units in my study. I want to pooled the data and then estimate a regression model in which I would have different intercepts and slopes for all the four cross sections. Actually I just only want a separate slope for one specific independent variable for all four cross sections. Can you help me how to make a model with different intercepts and slopes. And secondly how to make a spreadsheet.