[Gretl-users] Restricting a sample to specific time series

Hello I am a new gretl user and have a question whether and how it is possible to run a loop only via a selection of time series that have minimum length of 24 months. The series's have different start and end dates and I want to run a regression for each series that has a minimum of 24 data points. Is there anybody, who can hint me on how to restrict or define the loop properly. On possibility is, to preselect the data that I import into gretl but this would be tedious, because I will also run a different model on all series that have a minimum of 12 data point. Thanks in advance, Jan