semi-tricky sql query

i am perplexing query sql server 2005 nonetheless i can't figure out it. i have list following fields:

messageid int

categoryid int

priority tinyint

messagetext nvarchar(max)

i need query relapse * any quarrel top priority within category. example, i following data:

messageid, categoryid, priority, messagetext

1, 100, 1, blunder #1234 occurred

2, 100, 2, blunder #243 occurred

3, 100, 3, blunder #976 occurred

4, 200, 4, blunder #194 occurred

5, 200, 1, blunder #736 occurred

6, 300, 3, blunder #54 occurred

7, 300, 2, blunder #888 occurred

then outcome be:

messageid, categoryid, priority, messagetext

3, 100, 3, blunder #976 occurred

4, 200, 4, blunder #194 occurred

6, 300, 3, blunder #54 occurred

notice advantage quarrel per category, quarrel top priority category.

can anyone tell me i query?