Prioritizing activities that overlap in audience and page

[#1]

Hello, I'm new to Adobe Target, so this may be a basic question.

If I have multiple activities set up to deliver content on the same page to the same audience, can I control when a user sees one activity as opposed to another?

For example, say I have activity 1 and activity 2 with overlapping audiences that deliver content to the same page. Can I set a rule that says that if a user has never visited the page before he will see activity 1? After the visitor sees activity 1 three times, then he will see activity 2 going forward?

Assuming this is possible, does this go against best practices? Should collisions be avoided as a general rule?

Thanks,

Keith