I have experiment leading to 4-way ANOVA

 - 3 experimental groups
 - participants in each group responded to 70 trials
 - Reaction time as DV
 - trials were divided into separate groups by full factorial design by three variables A,B and C

I'm not sure what is the best way to analyze the data. I can run one 4-way ANOVA with (`RT ~ group*A*B*C`) or run three 3-way ANOVAs for each group separately (`RT ~ A*B*C`).

What is the best practice? Run one 4way ANOVA, but harder to interpret, or run three 3-way ANOVAs and correct for multiple testing?

thanks
Filip