Is it possible to subquery tasks?  I'd like to pull accounts that do not have an open task.

This is what I have:

for(account a: [select id, Name, ownerid, lastactivitydate FROM ACCOUNT WHERE ID IN (SELECT ACCOUNTID FROM task WHERE STATUS != 'NOT STARTED') AND lastactivitydate <:lastedit AND type = 'Active Opportunity' AND LastModifiedDate <:lastedit and ownerID !=: userinfo.getuserid() and LASTACTIVITYDATE!= NULL ORDER BY LastActivityDate Desc limit 150]) {
accountlist.add(new aAccount(a));
}

I am throwing this error:

Compile Error: Entity 'task' is not supported for semi join inner selects at line 35 column 24

Is there another way to pull all accounts that do not have an open task?