I would advise you sort your list by which form they signed up with.
You can do this by:
- Create two tags from the Subscriber main page (one for each of the forms you want to separate)
- Go to the first landing page
- Click Report on the top left tool ribbon
- Click on the subscriber number, which will take you to a list of confirmed subscribers who signed up with that particular page.
- Check the top checkbox
- In the Bulk Action menu, select Add Tag, and select the tag you want to link to this form.
- Repeat steps 2-6 for the second LP.
- When you write your broadcasts, or sequences, assign the relevant tag before sending it out.
It sounds complicated, but it isn't, honestly.
Hope this helps,