当连字符仅存在于带有正则表达式的第一行时，在第二行添加缺少连字符

问：

当连字符仅存在于第一行时，需要在第二行添加缺少的连字符：

24
00:03:01,848 --> 00:03:04,893
- How adorable.
[both laughing]

48
00:02:53,798 --> 00:02:54,758
[clears throat]

49
00:02:57,552 --> 00:02:59,971
- [clears throat] Phil.
What can I get you?

168
00:07:01,421 --> 00:07:03,048
Really?
- If that's possible, yeah.

169
00:07:03,089 --> 00:07:04,007
- Really?
- Mm-hmm.

以下是我认为可能有效的[不抽雪茄]：

Find:       ^([- ])(?=.*\r?\n([A-Za-z\[]))
Replace:    - $1

正确的最终结果如下，两行都有连字符：

24
00:03:01,848 --> 00:03:04,893
- How adorable.
- [both laughing]

48
00:02:53,798 --> 00:02:54,758
[clears throat]

49
00:02:57,552 --> 00:02:59,971
- [clears throat] Phil.
- What can I get you?

提前致谢，汉克