Yes you can!
Within Float you can group multiple categories together to show only a top line figure in the cash flow. To do this select 'Manage table layout' (from above the left side of the main cash flow table) and select the accounts that you would like to include in the group. This will activate the ‘Group rows’ button
which will allow you to name and create the group.
When an account is added to a group it will then show as part of that group in the main cash flow. When the group is closed only the group total will display however clicking on the group will open it to reveal the accounts contained within it.