I need to analyse some data (between group differences) that includes four participant groups but I'm not interested in making comparisons between all of them. I.e. I only want to compare group 1 v 2, 1 v 3, 2 v 4 and 3 v 4. So only 4 comparisons rather than the 6 that would be factored into an ANOVA. I know that with more than two groups you should use ANOVA but the power to detect a difference in the comparisons that I'm interested in is impacted upon by having the additional comparisons that I'm not. Would it be preferable to run 4 separate t-tests but then adjust the p-value to <0.0125 to be considered significant? Or can I run ANOVA's and somehow adjust the p-values to account for the fact that I'm ignoring two of the pairwise comparisons? I will also need to assess a change pre- to post-intervention in these groups, which I had planned to use mixed model ANOVA to do although I am again wondering if separate t-tests would be acceptable for the same reasons outlined above. Any advice would be greatly appreciated!