问如何排除第一组的单个字符与第二组的匹配？

EN

Full match  3-8 `DDDFF`
Group 1.    3-4 `D`
Group 2.    6-7 `F`

(.)\1{2}(.)\2{1}

Full match  5-10    `QQQQQ`
Group 1.    5-6 `Q`
Group 2.    8-9 `Q`

(.)\1{2}((?:\1))\2{1}


1st Capturing Group (.)
. matches any character (except for line terminators)
\1{2} matches the same text as most recently matched by the 1st capturing group
{2} Quantifier — Matches exactly 2 times
2nd Capturing Group ((?:\1))
Non-capturing group (?:\1)
\1 matches the same text as most recently matched by the 1st capturing group
\2{1} matches the same text as most recently matched by the 2nd capturing group
{1} Quantifier — Matches exactly one time (meaningless quantifier)