Groups_name col1    col2
group1  3   4
group1  1   1
group1  1   1
group2  1   1
group3  3   7
group3  1   1
group4  3   3
group4  1   1

Groups_name col1    col2
group1  3   4
group1  1   1
group1  1   1
group4  3   3
group4  1   1

tab %>%
  group_by(Groups_name) %>%
  filter(all(col1 == col2,col2-2,col2+2))  %>%
  filter(any(col1 > 1))